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  • 1995-1999  (21)
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  • 1995-1999  (21)
  • 1990-1994
  • 1975-1979
  • 1970-1974  (185)
Jahr
  • 1
    ISSN: 1364-6753
    Schlagwort(e): Key words Multiple sclerosis ; Genetics ; Myelin basic protein ; Myelin oligodendrocyte glycoprotein ; Proteolipid protein
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: ABSTRACT Multiple sclerosis (MS) is an autoimmune demyelinating disease of the central nervous system. A complex genetic etiology is thought to underlie susceptibility to this disease. The present study was designed to analyze whether differences in genes that encode myelin proteins influence susceptibility to MS. We performed linkage analysis of MS to markers in chromosomal regions that include the genes encoding myelin basic protein (MBP), proteolipid protein (PLP), myelin-associated glycoprotein (MAG), oligodendrocyte myelin glycoprotein (OMGP), and myelin oligodendrocyte glycoprotein (MOG) in a well-characterized population of 65 multiplex MS families consisting of 399 total individuals, 169 affected with MS and 102 affected sibpairs. Physical mapping data permitted placement of MAG and PLP genes on the Genethon genetic map; all other genes were mapped on the Genethon genetic map by linkage analysis. For each gene, at least one marker within the gene and/or two tightly linked flanking markers were analyzed. Marker data analysis employed a combination of genetic trait model-dependent (parametric) and model-independent linkage methods. Results indicate that MAG, MBP, OMGP, and PLP genes do not have a significant genetic effect on susceptibility to MS in this population. As MOG resides within the MHC, a potential role of the MOG gene could not be excluded.
    Materialart: Digitale Medien
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  • 2
    Digitale Medien
    Digitale Medien
    Springer
    Italian journal of neurological sciences 20 (1999), S. 89-108 
    ISSN: 1126-5442
    Schlagwort(e): Key words Neurofibromatosis ; Nf1 ; Nf2 ; Mosaic/segmental neurofibromatosis ; Variants ; Classification ; Neurological manifestations ; Genetics ; Childhood ; Adulthood
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract The last two decades have seen clinical and molecular delineation of the different forms of neurofibromatosis. Differentiation of these forms is not just an academic exercise: their natural history, management and genetic counselling are quite different. Of the numerical classifications of neurofibromatosis proposed in the past, only neurofibromatosis type 1 (Nf1) and neurofibromatosis type 2 (Nf2) are now well delineated clinically and have been shown to be distinct at the molecular level. For both forms of neurofibromatosis, patients with clinical generalised disease have been demonstrated to be mosaic at the molecular level, and features of segmental or mosaic Nf1 and Nf2 have been delineated. Other reported forms of neurofibromatosis are rarer; they include Watson syndrome, hereditary spinal neurofibromatosis, familial intestinal neurofibromatosis, autosomal dominant café-au-lait spots alone, autosomal dominant neurofibromas alone, and schwannomatosis, the latter believed to be a variant of Nf2. Further delineation is neeeded for individuals having overlapping features of Noonan's syndrome and neurofibromatosis (the so-called Noonan/neurofibromatosis syndrome) and the syndrome of “multiple naevi, multiple schwannomas and multiple vaginal leiomyomas”. In this article we review the forms of neurofibromatosis which we believe are true clinical entities. Particular attention is given to the neurological manifestations of neurofibromatosis.
    Materialart: Digitale Medien
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  • 3
    ISSN: 1432-1440
    Schlagwort(e): Key words Diabetes ; Genetics ; Phosphofructokinase ; Glycogenosis ; NIDDM ; PFK
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract The etiology of non-insulin-dependent diabetes mellitus (NIDDM) is usually explained as a combination of peripheral insulin resistance and impaired beta-cell function. Phosphofructo-1-kinase (PFK1) is a rate limiting enzyme in glycolysis, and its muscle subtype (PFK1-M) deficiency leads to an autosomal recessively inherited disorder known as glycogenosis type VII or Tarui’s disease. It was evaluated whether PFK1-M deficiency leads to NIDDM in humans. A core family of four was evaluated for PFK1-M deficiency by DNA- and enzyme-activity-analyses. All members underwent oral and intravenous glucose tolerance test (oGTT/ivgtt), as well as an insulin sensitivity test (IST) using octreotide. Results: Father (46 years, BMI 22.4 kg/m2) and older son (19 years, BMI 17.8 kg/m5) showed homozygous PFK1-M deficiency, while mother (47 years, BMI 28.4 kg/m5) and younger son (13 years, BMI 16.5 kg/m5) were shown to be heterozygously PFK1-M-deficient on enzyme activity levels. DNA analysis revealed an exon 5-missense-mutation at one allele of all four members, and an exon 22-frameshift-mutation at the other allele of the two homozygously affected individuals. By oGTT the father showed impaired glucose tolerance, and the mother clinical diabetes. By ivGTT both parents and the older son had a decreased first phase insulin secretion, and a diminished glucose disappearance rate. The IST showed marked insulin resistance in both parents and the older son, and moderate resistance in the younger son, previously not described. Conclusion: PFK1-M-deficiency leads to a metabolic state typical for early NIDDM in homozygously affected humans, especially concerning insulin resistance and loss of first phase beta-cell insulin secretion, and may contribute to the manifestation of NIDDM in a subgroup of patients.
    Materialart: Digitale Medien
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  • 4
    Digitale Medien
    Digitale Medien
    Springer
    Der Nervenarzt 70 (1999), S. 195-205 
    ISSN: 1433-0407
    Schlagwort(e): Schlüsselwörter Alzheimer-Krankheit ; Genetik ; Risikofaktoren ; Genetische Beratung ; Key words Alzheimer’s disease ; Genetics ; Risk factors ; Genetic counseling
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Summary A multifactorial etiology underlies the majority of cases of Alzheimer’s disease (AD). Both ill-defined environmental and genetic factors contribute to the development of the disease. Allele ɛ4 of ApoE is a genetic risk factor. Its presence increases the risk of developing AD. However, presence of e4 is neither necessary nor sufficient for the disease to arise. Apart from the common multifactorial forms of the disease, there are rare variants which are inherited as Mendelian traits. To date three genes are known that can be mutated in these rare forms of AD. Of these, mutations in the gene presenilin 1 on chromosome 14 are most frequent. In addition, mutations in the gene presenilin 2 on chromosome 1 and in the amyloid precursor protein gene (APP on chromosome 21) occur in autosomal dominant AD. This article reviews our present knowledge of the genetics of AD and discusses its relevance for patients with AD and their relatives.
    Notizen: Zusammenfassung Der Großteil der Fälle von Alzheimer-Krankheit (AK) hat eine multifaktorielle Ätiologie. Das bedeutet, bisher nicht genauer bekannte Umwelteinflüsse und genetische Faktoren spielen bei der Entwicklung der Krankheit eine wesentliche Rolle. Von seiten der Genetik unterscheidet man bei der AK gegenwärtig genetische Risikofaktroren und Mutationen. Der einzige bisher gesicherte genetische Risikofaktor ist das Allel ɛ4 des Gens für Apolipoprotein E auf Chromosom 19. Dieses Allel erhöht die Wahrscheinlichkeit, an der AK zu erkranken, ist jedoch weder eine notwendige noch eine hinreichende Bedingung. Neben den häufigen Formen mit multifaktorieller Ätiologie kommen seltene Varianten der Krankheit vor, die nach Mendelschen Regeln vererbt werden. Bisher sind 3 Gene bekannt, die bei diesen seltenen, in der Regel früh auftretenden und autosomal dominant vererbten Formen mutiert sein können. Am häufigsten findet sich bei den autosomal-dominanten Fällen eine Mutation im Gen präsenilin 1 auf Chromosom 14, seltener liegen Mutationen im Gen präsenilin 2 auf Chromosom 1 und im Gen des Amyloid- Vorläuferproteins auf Chromosom 21 vor. In diesem Beitrag geben wir eine Übersicht über gegenwärtige Befunde zur Genetik der AK und diskutieren die Bedeutung dieses Wissens für Patienten und deren Verwandte.
    Materialart: Digitale Medien
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  • 5
    Digitale Medien
    Digitale Medien
    Springer
    Der Nervenarzt 70 (1999), S. 955-969 
    ISSN: 1433-0407
    Schlagwort(e): Schlüsselwörter Schizophrenie ; Genetik ; Schizophrenes Spektrum ; Kopplungsuntersuchungen ; Assoziationsuntersuchungen ; Key words Schizophrenia ; Genetics ; Schizophrenia spectrum ; Linkage studies ; Association studies
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Summary Schizophrenia is a genetic complex disease as it does not follow monogenic transmission while non-familial environmental factors have a strong additional impact. A heterogenous, continuous phenotype is transmitted in families which can now be more precisely characterized. Genes coding for proteins with presumed pathophysiological relevance are apparently not playing a major causal role. However, in the last three years several (currently seven) candidate regions have been identified in a replicable manner by linkage studies. These regions are likely to host susceptibility genes for schizophrenia, but none of them has been identified up to now. Given these findings, polygenic transmission has now become very likely. The candidate regions are currently being narrowed down by various promising techniques.
    Notizen: Zusammenfassung Die Schizophrenie gehört zu den genetisch komplexen Erkrankungen, die keinem monogenen Erbgang folgen und bei denen auch nichtfamiliäre Umgebungsfaktoren eine wichtige Rolle spielen. Dabei wird intrafamiliär ein heterogener, quantitativ variierender Phänotyp übertragen, der zunehmend genauer charakterisiert werden kann. Keines der bekannten Gene mit vermuteter pathophysiologischer Relevanz spielt nach den bisherigen Erkenntnissen eine substantielle Rolle. In den vergangenen drei Jahren ist es aber erstmals durch Kopplungsuntersuchungen gelungen, mehrere replizierbare Kandidatenregionen (derzeit sieben) auf dem Genom zu identifizieren, in denen vermutlich Suszeptibilitätsgene für Schizophrenie liegen. Keines dieser Gene wurde jedoch bislang identifiziert. Mit diesen Befunden ist eine polygene Übertragung der Schizophrenie sehr wahrscheinlich geworden. Verschiedene Techniken zur Eingrenzung der Kandidatenregionen werden derzeit erfolgreich angewandt.
    Materialart: Digitale Medien
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  • 6
    ISSN: 1432-0533
    Schlagwort(e): Key words Frontotemporal dementia ; Genetics ; Progressive supranuclear palsy ; Tauopathy ; Exon ; amplifcation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Recently intronic and exonic mutations in the Tau gene have been found to be associated with familial neurodegenerative syndromes characterized not only by a predominantly frontotemporal dementia but also by the presence of neurological signs consistent with the dysfunction of multiple subcortical neuronal circuitries. Among families, the symptomatology appears to vary in quality and severity in relation to the specific Tau gene mutation and often may include parkinsonism, supranuclear palsies, and/or myoclonus, in addition to dementia. We carried out molecular genetic and neuropathological studies on two patients from a French family presenting, early in their fifth decade, a cognitive impairment and supranuclear palsy followed by an akinetic rigid syndrome and dementia. The proband died severely demented 7 years after the onset of the symptoms; currently, his brother is still alive although his disease is progressing. In both patients, we found a Tau gene mutation in exon 10 at codon 279, resulting in an asparagine to lysine substitution (N279K). Neuropathologically, widespread neuronal and glial tau accumulation in the cortex, basal ganglia, brain stem nuclei as well as in the white matter were the hallmark of the disease. These deposits were shown by immunohistochemistry and immunoelectron microscopy, using a battery of antibodies to phosphorylation-dependent and phosphorylation-independent epitopes present in multiple tau regions. In the neocortex, tau-immunopositive glial cells were more numerous than immunopositive neurons; the deeper cortical layers as well as the white matter adjacent to the cortex contained the largest amount of immunolabeled glial cells. In contrast, some brain stem nuclei contained more neurons with tau deposits than immunolabeled glial cells. The correlation of clinical, neuropathological and molecular genetic findings emphasize the phenotypic heterogeneitiy of diseases caused by Tau gene mutations. Furthermore, to test the effect of the N279K mutation and compare it with the effect of the P301L exon 10 mutation on alternative splicing of Tau exon 10, we used an exon amplification assay. Our results suggest that the N279K mutation affects splicing similar to the intronic mutations, allowing exon 10 to be incorporated more frequently in the Tau transcript.
    Materialart: Digitale Medien
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  • 7
    Digitale Medien
    Digitale Medien
    Springer
    Annals of hematology 78 (1999), S. 485-494 
    ISSN: 1432-0584
    Schlagwort(e): Key words Mantle cell lymphoma ; Classification ; Pathology ; Prognosis ; Immunology ; Genetics ; Antineoplastic agents ; Combined ; Therapeutic use ; Radiotherapy ; Hematopoietic stem cell transplantation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Materialart: Digitale Medien
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  • 8
    ISSN: 1432-0584
    Schlagwort(e): Key words Acute leukemia ; Genetics ; Sex ; ABO Blood group
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  Acute leukemia is more common in males at almost every age, and this fact remains unexplained. A study was carried out in northeast peninsular Malaysia, where the population is predominantly Malay, to examine whether there was a difference in ABO blood group distribution between males and females with acute leukemia (AL). The ABO blood groups of 109 male and 79 female patients with AL (98 ALL, 90 AML) were compared with those of 1019 controls. In the control population, 39.7% were group O. Among males with AL, 39.4% were group O, whereas among females with AL, the proportion was 24.1% (p=0.03). The same trend to a lower proportion of group O among females was seen if the group was divided into adult/pediatric or lymphoblastic/myeloblastic groups, though these differences were not statistically significant. If these findings can be confirmed, they suggest the presence of a "sex-responsive" gene near to the ABO gene locus on chromosome 9, which relatively protects group O women against AL, at least in our population. The existence of such a gene might also partly explain why acute leukemia, and possibly other childhood cancers, are more common in males.
    Materialart: Digitale Medien
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  • 9
    ISSN: 1423-0127
    Schlagwort(e): Tax ; HTLV-1 ; Trans-activation ; Phosphorylation ; Mutagenesis ; Transcription ; Genetics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract The human T cell leukemia virus type 1 (HTLV-1) Tax is a phosphoprotein, however, the contribution of phosphorylation to Tax activity is unknown. Previous studies have shown that phosphorylation of Tax occurs on serine residue(s), within one tryptic fragment, in response to 4β-phorbol-12β-myristate-13α-acetate, in both mouse and human cells. Studies were conducted in multiple cell lines to identify the specific phosphorylated serines as a prelude to functional analysis. The phosphorylation pattern of Tax was found to be different in 293T and COS-7 cells in comparison with MT-4 and Px-1 cells. However, one tryptic fragment remained consistent in comigration analyses among all cell lines. Using selected Tax serine mutants a tryptic fragment containing a serine at residue 113 believed to be the site of phosphorylation of Tax did not comigrate with the common phosphorylated tryptic fragment. Analysis of selected Tax mutants for ability totrans-activate the cytomegalovirus promoter demonstrated mutation of serine 77 to alanine reducedtrans-activation by 90% compared to wild-type Tax. However, examination of the phosphorylation pattern of the serine 77 mutant demonstrated that it is not the site of phosphorylation. These studies demonstrate the importance of using relevant cell lines to characterize the role of phosphorylation in protein function.
    Materialart: Digitale Medien
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  • 10
    ISSN: 1432-1963
    Schlagwort(e): Schlüsselwörter Rhadomyosarkom ; Klassifizierung ; Immunhistochemie ; Genetik ; Prognose ; Key words Rhabdomyosarcoma ; Classification ; Immunohistochemistry ; Genetics ; Prognosis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Summary Rhabdomyosarcoma (RMS) is the most important and a very heterogeneous group of malignant soft tissue tumors of childhood and adolescence.The two major subtypes (embryonal and alveolar) share a common myogenic differentiation, but seem to be histogenetically not related. The so-called ’International Classification of Rhabdomyosarcoma’ includes, besides the two major subtypes, the botryoid and leiomyomatous subtypes of embryonal RMS which are associated with a better prognosis and are treated less aggressively according to current protocols. In addition, the solid variant of alveolar RMS is included in the alveolar group of RMS. The identification of the various subtypes is necessary and important because the treatment with the current protocols is also related to histology. Using conventional stains and immunohistochemistry, these subtypes are distinguishable. Genetic analysis can be helpful in the demonstration of t(2;13) or t(1;13) translocations in alveolar RMS. The identification of alveolar RMS with t(1;13) translocation might become important in the future, because this type of translocation seems to be related to a better prognosis as compared to tumors with a t(2;13) translocation.
    Notizen: Zusammenfassung Rhabdomyosarkome stellen eine heterogene Gruppe von ganz verschiedenartigen, histogenetisch wohl nicht zusammengehörenden Tumoren dar. Nach der heute verwendeten „Internationalen Klassifikation” der Rhabdomyosarkome werden neben der Unterteilung in embryonalen und alveoläre Rhabdomyossarkome auch Subtypen des embryonalen RMS identifiziert (botryoider und leiomyomatöser Subtyp), die durch eine günstigere Prognose und durch die Notwendigkeit einer weniger aggressive Therapie gekennzeichnet sind. Durch Einsatz von verschiedenen histologischen und immunhistochemischen Färbungen ist die Identifizierung der verschiedenen Typen der RMS heute möglich und auch zwingend notwendig, da die einzelnen Entitäten nach ganz unterschiedlichen Therapieprotokollen behandelt werden. Der Nachweis typischer molekulargenetischer Veränderungen kann in der Unterscheidung insbesondere von embryonalen und alveolären RMS hilfreich sein. In der Regel ist die Abgrenzung zwischen diesen beiden Entitäten auch an konventionell gefärbten Schnittpräparaten möglich. Die Identifizierung von alveolären RMS mit einer t(1;13)-Translokation könnte in Zukunft eine große Bedeutung haben, da diese genetische Veränderung möglicherweise mit einer günstigeren Prognose assoziert sein könnte als die t(2;13)-Translokation.
    Materialart: Digitale Medien
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  • 11
    Digitale Medien
    Digitale Medien
    Springer
    European journal of pediatrics 158 (1999), S. 302-307 
    ISSN: 1432-1076
    Schlagwort(e): Key words Congenital heart disease ; Pulmonary atresia and ventricular septal defect ; Genetics ; Monosomy 22q11.2
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract The purpose of our study was to describe the prevalence and the clinical spectrum of monosomy 22q11.2 in a population of patients with pulmonary atresia and ventricular septal defect. We examined all 44 patients with this conotruncal cardiac malformation who presented to our institution from January 1994 until December 1997. The type of collateral lung perfusion was recorded including anomalies of the pulmonary arteries as well as facial and immunological abnormalities. Molecular-cytogenetic testing for a 22q11.2 microdeletion was performed using the probes D22S75 and cHKAD26. Statistical differences were evaluated with the Fisher's Exact Test. Monosomy 22q11.2 was present in ten children (23%) with major aortopulmonary collateral arteries (group 1). The remaining 13 children (29%) with major aortopulmonary collateral arteries (group 2) and all 21 children (48%) with ductus arteriosus (group 3) were negative for this microdeletion. All children in group 1 had facial anomalies, six had mild immunological abnormalities including decreased CD 4+ or CD 8+ cells. Anomalies of the pulmonary vascular bed were significantly more frequent in children of group 1 (9/10) than in children of group 2 (4/13) or group 3 (0/21). Due to these pulmonary vascular anomalies, corrective surgery had been accomplished in fewer children with monosomy 22q11.2 (none in group 1) as compared to 7/13 children in group 2 and 14/21 children in group 3. Conclusion In children with pulmonary atresia and ventricular septal defect, monosomy 22q11.2 is preferentially associated with major aortopulmonary collateral arteries. Due to the higher incidence of pulmonary arterial abnormalities, successful surgical repair will require a different therapeutic approach in most patients with this microdeletion.
    Materialart: Digitale Medien
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  • 12
    Digitale Medien
    Digitale Medien
    Springer
    Current genetics 35 (1999), S. 571-584 
    ISSN: 1432-0983
    Schlagwort(e): Key words Cytokinesis ; Kinase ; Mitosis ; Schizosaccharomyces pombe ; Cell division ; Phosphatase ; Mutant ; Genetics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The fission yeast Schizosaccharomyces pombe provides a simple eukaryotic model for the study of cytokinesis. S. pombe cells are rod-shaped, grow mainly by elongation at their tips, and divide by binary fission after forming a centrally placed division septum. Analysis of mutants has begun to shed light upon how septum formation and cytokinesis are regulated both spatially and temporally. Some of the proteins involved in these events have been functionally conserved throughout eukaryotic evolution, suggesting that aspects of this control will be common to all eukaryotic cells.
    Materialart: Digitale Medien
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  • 13
    Digitale Medien
    Digitale Medien
    Springer
    Journal of neurology 246 (1999), S. 1140-1144 
    ISSN: 1432-1459
    Schlagwort(e): Key words Amyotrophic lateral sclerosis ; Genetics ; Glutamate transporter gene
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Amyotrophic lateral sclerosis (ALS) is a progressive neurological disorder characterised by degeneration of upper and lower motor neurons. Whilst the primary pathogenic trigger is unknown in most cases, evidence is mounting to implicate a role for glutamate-mediated neurotoxicity in the disorder. Recent studies have shown reduced levels of the mainly astroglial glutamate transporter EAAT2 in ALS motor cortex and spinal cord and multiple abnormal EAAT2 mRNA species in ALS brain tissue. One cause of the low EAAT2 levels may be that point mutations in the EAAT2 gene, EAAT2, result in an abnormal unstable protein. To test this hypothesis we analysed EAAT2 in 128 sporadic and 23 familial European ALS cases. No variants within the coding sequence of EAAT2 to affect the protein sequence nor in the consensus splice sites of the flanking intronic sequences were found in any cases, similar to findings in other reports. Frequent polymorphisms within the flanking intronic sequences of both exons 2 and 4 were seen but at similar frequencies in controls. Mechanisms other than mutations within the coding region of EAAT2 must therefore be responsible for the low levels of EAAT2 seen in most cases of ALS.
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  • 14
    Digitale Medien
    Digitale Medien
    Springer
    International journal of colorectal disease 14 (1999), S. 2-9 
    ISSN: 1432-1262
    Schlagwort(e): Key words Inflammatory bowel disease ; Crohn's disease ; Ulcerative colitis ; Epidemiology ; Genetics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Inflammatory bowel diseases (IBD) are complex disorders. While the exact etiology of these diseases remains unknown, recent progress in the epidemiology and genetics of IBD has clearly demonstrated both environmental and genetic factors to play a role in the development of the disease, and it is expected that some risk factors are common for both Crohn's disease (CD) and ulcerative colitis (UC). The environmental factor(s) are associated with the Western way of life in the second half of the twentieth century. Cigarette smoking is presently the best known environmental factor. However, the effect of tobacco is opposite in CD and UC. A familial history of IBD is the most important risk factor for developing the disease, suggesting a genetic predisposition to IBD. This hypothesis has recently been confirmed by the localization of at least two susceptibility loci on chromosomes 12 and 16. These genes seem to play a role in both CD and UC. They must now to be identified.
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  • 15
    Digitale Medien
    Digitale Medien
    Springer
    Child's nervous system 15 (1999), S. 676-680 
    ISSN: 1433-0350
    Schlagwort(e): Key words Craniosynostosis ; Genetics ; FGFR ; Msx2 ; Development ; Skull
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  The genetic studies of syndromic craniosynostoses lead to the characterisation of genes that regulate the correct development of the bones of the skull. From these studies, it appears that FGF/FGFR signalling has a crucial role in this problem. Numerous mutations affecting the genes coding for FGFR1, 2 or 3 are responsible for these syndromes. It is interesting to note that some identical mutations produced various different phenotypes, suggesting that other genes modulate the phenotypic expressivity. The other involved genes in these syndromes code for such proteins as Msx2 or Twist that interact in the cellular pathways responsible for FGF action. From these genetic studies, it is now important to establish the role of these proteins during the development of the skull. Msx2 plays a repressive role in osteogenesis, whereas FGFRs act as promoting proteins. In the near future, it will be very important to improve our understanding of these phenomena in order to test specific treatments to prevent the development of such syndromes.
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  • 16
    Digitale Medien
    Digitale Medien
    Springer
    Journal of neurology 246 (1999), S. 69-72 
    ISSN: 1432-1459
    Schlagwort(e): Key words Alzheimer’s disease ; Genetics ; Genetic counseling ; Predictive testing ; Diagnosis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Alzheimer’s disease (AD) has a significant genetic background manifested as autosomal dominant inheritance in some early-onset families and as familial risk in late-onset cases. Three genes responsible for early-onset autosomal dominant AD have been identified, and one gene, apolipoprotein E, has been confirmed as a susceptibility gene for late-onset forms of the disorder. These findings raise the possibility of genetic testing, either for early diagnosis or prediction. For early-onset autosomal dominant AD genetic testing will have a limited but useful role in confirming diagnosis in established cases and in predictive counselling for relatives; a situation analogous to that for Huntington’s disease. For late-onset AD significant problems remain to be overcome before the advances in molecular genetics have a direct clinical application
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  • 17
    ISSN: 1432-5233
    Schlagwort(e): Key words Mitochondrial DNA ; Genetics ; Maternally inherited diabetes mellitus ; Deafness ; np 3243 mutation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Mitochondrial DNA (mtDNA) gene defects may play a role in the development of maternally inherited diabetes mellitus and deafness (MIDD). A family from Southern Italy who showed maternal transmission of type 2 diabetes mellitus with three individuals affected is described. A 10.4 kb deletion and mutations at nucleotide positions (np) 3243, 7445 and 11778 in the mtDNA of six relatives were sought. The mitochondrial np 3243 mutation of the tRNA Leu (UUR) gene was identified in a boy affected by optic atrophy and mental retardation, as well as in his diabetic mother. No other mutations or deletions were found. Our study points out the variable phenotypic expression of the np 3243 mtDNA mutation. This may suggest the presence of other mitochondrial or nuclear mutations required to modulate the phenotype. A clinical and metabolic follow-up of all family members was necessary to understand the role of the np 3243 mutation, especially in one child affected by optic atrophy and mental retardation. Further studies will be aimed at investigating the prevalence of mutations and deletions of mtDNA in type 2 diabetes mellitus.
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  • 18
    ISSN: 1432-2242
    Schlagwort(e): Key words Passiflora ; Self-incompatibility ; Genetics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract  The self-incompatibility in yellow passion fruit was previously described as homomorphic sporophytic with monofactorial inheritance. Five progenies were obtained by bud-selfing. The plants of these progenies were selfed, reciprocally crossed within each progeny and crossed with known incompatible phenotypes to identify their phenotypic group. Fruit set was evaluated at the 7th day after pollination. Two progenies consisted of two self-incompatible groups, the other three formed three suck groups. The groups were identified as S1, S2, S3, S4, S5 and S6. The results provide evidence that the self-incompatibility of passion fruit is controlled by two loci, the S-gene and another, whose expression needs to be investigated.
    Materialart: Digitale Medien
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  • 19
    ISSN: 1432-2242
    Schlagwort(e): Key words Simple sequence repeat (SSR) ; Microsatellites ; Molecular markers ; Genetics ; Fingerprinting
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract  We report the sequences of 17 primer pairs of microsatellite loci, which we have cloned and sequenced from two genomic libraries of peach [Prunus persica (L) Batsch] ‘Redhaven’, enriched for AC/GT and AG/CT repeats respectively. For ten of these microsatellite loci we were able to demonstrate Mendelian inheritance in a segregating back-cross population; the remainder did not segregate. The polymorphism of the microsatellites was evaluated in a panel of ten peach genotypes, including true-to-type peaches, nectarines and one canning-peach. Fifteen microsatellites (88%) were polymorphic showing 2–4 alleles each. The mean heterozygosity, averaged over all loci, was 0.32 and significantly higher than that reported in the literature for isozymes and molecular markers, such as RFLPs and RAPDs. We have also assayed the cross-species transportability and found that ten microsatellite (59%) gave apparently correct amplification in all Prunus species surveyed, namely P. domestica (European plum), P. salicina (Japanese plum), P. armeniaca (apricot), P. dulcis (almond), P. persica var. vulgaris (peach), P. persica var. laevis (nectarine), P. avium (sweet cherry) and P. cerasus (sour cherry), with three of them also being amplified in Malus (apple). The remaining microsatellites gave less-extensive amplification. Because of their appreciable polymorphism and wide cross-species transportability, most of these new markers can be integrated into the linkage maps which are currently being constructed in peach, as well as in other stone fruit crops, such as almond, apricot, cherry and plum.
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  • 20
    Digitale Medien
    Digitale Medien
    Springer
    Theoretical and applied genetics 99 (1999), S. 800-810 
    ISSN: 1432-2242
    Schlagwort(e): Key words Almond ; Compatibility ; Genetics ; Prunus dulcis ; Ribonucleases
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract  Six almond progenies, each the product of a cross between a self-compatible and a self-incompatible parent, were analysed for stylar ribonucleases. Proteins were extracted and separated using non-equilibrium pH gradient electrofocusing (NEPHGE), and the gels were stained for ribonuclease activity. Most seedlings showed either two principal bands, interpreted as corresponding to two incompatibility alleles, or a single band. The seedlings were also bagged in the field at flowering time to determine fruit set after selfing, and some were also examined for the growth of pollen-tubes in selfed styles using UV fluorescence microscopy. With very few exceptions, those seedlings showing single-banded zymograms were found to be self-compatible according to field and microscope studies, and those with two bands were found to be self-incompatible. We conclude that the allele for self-compatibility in almond does not code for ribonuclease activity and that the ribonuclease isoenzyme assay is a convenient technique for predicting self-compatibility in segregating progenies. A novel band in two derivatives of ’Ferrastar’ was ascribed to a new incompatibility allele, S 10 .
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  • 21
    Digitale Medien
    Digitale Medien
    Springer
    Behavioral ecology and sociobiology 46 (1999), S. 171-179 
    ISSN: 1432-0762
    Schlagwort(e): Key words Honeybee ; Apis mellifera ; Division of labor ; Genetics ; Pollen foraging
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract  A fundamental requirement of task regulation in social groups is that it must allow colony flexibility. We tested assumptions of three task regulation models for how honeybee colonies respond to graded changes in need for a specific task, pollen foraging. We gradually changed colony pollen stores and measured behavioral and genotypic changes in the foraging population. Colonies did not respond in a graded manner, but in six of seven cases showed a stepwise change in foraging activity as pollen storage levels moved beyond a set point. Changes in colony performance resulted from changes in recruitment of new foragers to pollen collection, rather than from changes in individual foraging effort. Where we were able to track genotypic variation, increases in pollen foraging were accompanied by a corresponding increase in the genotypic diversity of pollen foragers. Our data support previous findings that genotypic variation plays an important role in task regulation. However, the stepwise change in colony behavior suggests that colony foraging flexibility is best explained by an integrated model incorporating genotypic variation in task choice, but in which colony response is amplified by social interactions.
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  • 22
    Digitale Medien
    Digitale Medien
    Springer
    Journal of neurology 202 (1972), S. 241-246 
    ISSN: 1432-1459
    Schlagwort(e): Twins, Monozygotic ; Muscular Dystrophy, Progressive ; Duchenne Type of Progressive Muscular Dystrophy ; Genetics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The observation of a couple of concordant monozygotic twins with X-recessive progressive muscular dystrophy of Duchenne's type is presented. Their mother did not show any characteristic of a carrier despite the pluridimensional investigations including electron microscopy. The authors suggest in this situation a point mutation before the first cellular division at the origin of the gestation of the two dystrophic twins. However, there is also the possibility that the mother of the twins is a heterozygote in whom the carrier state could not be diagnosed by the available methods.
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  • 23
    Digitale Medien
    Digitale Medien
    Springer
    Archives of dermatological research 244 (1972), S. 347-350 
    ISSN: 1432-069X
    Schlagwort(e): Dermatitis atopica ; Genetics ; Solitary cases ; Organs struck ; Formation of reagins ; Hereditary prognosis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Zusammenfassend 1. Die Disposition zur Neurodermitis atopica wird entweder durch ein multifaktorielles System oder ein autosomal-dominantes Hauptgen vererbt. 2. Sowohl die sporadische als auch die familiäre Neurodermitis ist wahrscheinlich genetisch prädisponiert. 3. Für die Vergesellschaftung von Neurodermitis atopica mit Asthma bronchiale und Rhinitis atopica sind genetische Faktoren ausschließlich oder entscheidend verantwortlich. 4. Die Organwahl, d. h. ob die Atopie sich an der Haut oder im Bereich des Respirationstraktes manifestiert, wird vom Genotyp gesteuert. 5. Die Tendenz zur Reaginbildung ist genetisch fixiert, die Art der Reaginbildung ist aber ausschließlich oder weitgehend von Umwelteinflüssen abhängig. 6. Die chromosomale Konstellation XX respektive XY erleichtert respektive erschwert das Manifestwerden der Neurodermitis. 7. Es bestehen keine Anhaltspunkte dafür, daß die Schwere der Erkrankung und das Manifestationsalter vom Genotyp gesteuert werden.
    Materialart: Digitale Medien
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  • 24
    Digitale Medien
    Digitale Medien
    Springer
    European archives of psychiatry and clinical neuroscience 215 (1972), S. 362-375 
    ISSN: 1433-8491
    Schlagwort(e): Progressive Myoclonus Epilepsies ; Genetic Types ; Clinical Syndromes ; Pathomorphology ; Genetics ; Progressive Myoklonusepilepsien ; Erbtypen ; Klinik ; Pathomorphologie ; Genetik
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung Die Datenanalyse aller pathomorphologisch gesicherten Literatur- und eigenen Fälle mit zureichenden klinischen und genetischen Angaben macht die Annahme von vier Erbtypen oder Krankheitsformen der progressiven Myoklonusepilepsien (PME) wahrscheinlich: 1. Früh- oder Hauptform der PME des Typs Lafora. Erkrankungsalter: meist 12–17 Jahre. Rasche Progredienz und vorwiegend schwere Symptomenausprägung. Sterbealter: meist 18–22 Jahre. Allgemeine, ZNS-betonte Mucopolysaccharidspeicherkrankheit. „Laforakörperchen“. Autosomal recessiver Erbgang. Fragliche klinische Heterozygotenbefunde: Epilepsien, EEG-Anomalien, Myoklonien, Psychosen, Psychopathien. Wahrscheinlicher biochemischer Homo- und Heterozygotenbefund: Erhöhte Mucopolysaccharidharnausscheidung (Heparitinsulfat). 2. Spätform der PME des Typs Lafora. Erkrankungsalter: 17–33 Jahre. Langsamere Progredienz und weniger schwere Symptomenausprägung. Sterbealter: 42–65 Jahre. Allgemeine, ZNS-betonte Mucopolysaccharidspeicherkrankheit. „Laforakörperchen“. Geringere Speicherungsintensität. Autosomal recessiver Erbgang (multiple Allelie? Heterogenie?). Fragliche klinische Heterozygotenbefunde: Epilepsien. 3. Form der PME mit degenerativen ZNS-Veränderungen. Erkrankungsalter: meist 10–14 Jahre. Langsame Progredienz und vorwiegend leichtere Symptomenausprägung. Sterbealter: meist 25–35 Jahre. Degenerative Veränderungen der Zwischen- und Mittelhirnkerne, der Oliven, des Zahnkerns und der Kleinhirnrinde. Autosomal recessiver Erbgang. Fragliche klinische Heterozygotenbefunde: Verschiedenartige neuropsychiatrische Anomalien. 4. Form der PME mit degenerativen ZNS-Veränderungen. Erkrankungsalter: meist späte Kindheit. Erhebliche klinische Variabilität. Langsame Progredienz und vorwiegend leichtere Symptomenausprägung. Sterbealter: 30 bis über 70 Jahre. Autosomal dominanter Erbgang.
    Notizen: Summary All pathomorphological verified cases of the literature and our own investigations with sufficient clinical and genetic data are analysed. Results: Four genetic types or manifestations of the progressive myoclonus epilepsies (PME) are probable: 1. The Early or Main Type of the PME of Lafora Type. Age at onset: mostly between 12 and 17 years. Rapid progression and mainly severe symptoms. Age at death: mostly between 18 and 22 years. CNS-accentuated mucopolysaccharidethesaurismosis. “Lafora bodies”. Autosomal recessive mode of inheritance. Questionable clinical heterozygote findings: Epilepsies, EEG-anomalies, myoclonus, psychoses, psychopathies. Probable biochemical homo- and heterozygote findings: Increased mucopolysaccharide-micturition (heparitin sulfate). 2. The Late Type of the PME of Lafora Type. Age at onset: between 17 and 33 years. Slower progression and less severe symptoms. Age at death: between 42 and 65 years. CNS-accentuated mucopolysaccharide-thesaurismosis. “Lafora bodies”. Decreased intensity of thesaurismosis. Autosomal recessive mode of inheritance (multiple allelism? genetic heterogeneity?). Questionable clinical heterozygote findings: Epilepsies. 3. Type of the PME with Degenerative Changes of CNS. Age at onset: mostly between 10 and 14 years. Slow progression and mainly low-grade symptoms. Age at death: mostly between 25 and 35 years. Degenerative changes of the diencephalon and mesencephalon, of the olives, the dentate nucleus and the cerebellar cortex. Autosomal recessive mode of inheritance. Questionable clinical heterozygote findings: Various neuropsychiatric anomalies. 4. Type of the PME with Degenerative Changes of CNS. Age at onset: mostly late childhood. Considerable clinical variability. Slow progression and mainly low-grade symptoms. Age at death: between 30 and over 70 years. Autosomal dominant mode of inheritance.
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  • 25
    Digitale Medien
    Digitale Medien
    Springer
    European archives of psychiatry and clinical neuroscience 215 (1972), S. 240-251 
    ISSN: 1433-8491
    Schlagwort(e): Schizophreniform Psychoses ; Genetics ; Schizophrenieartige Psychosen ; Genetik
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung Zur nosologisehen Zuordnung schizophrenieartiger Psychosen dient in erster Linie die genetische Familienforschung, dann die Feststellung quantifizierbarer Variabeln: Manifestationsperiode, Geschlechtsverteilung, Verlaufstyp. Als „Maß“ für das schizophrenogene Erbe kann man die Geschwistermorbidität an Schizophrenie nehmen. Diese erlaubt eine Reihe von Psychosen zur Gruppe der Schizophrenien zu rechnen: die Spätschizophrenie, die Paranoia, die symbiontischen Psychosen. Einige schizophrenieartige Psychosen haben in der Verwandtschaft eine etwas verminderte Schizophreniemorbidität, einige keine gegenüber dem Durchschnitt erhöhte. Am Beispiel der symbiontischen Psychosen wird der Wert der genetischen und statistischen Forschung für die nosologische Bestimmung gezeigt. Abschließend werden Folgerungen aus dieser Darstellung schizophrenieartiger Psychosen gezogen.
    Notizen: Summary The genetic family investigation is one of the primary instruments for the nosological study of schizophrenia-like psychoses. The morbidity risk figures for schizophrenia of the siblings may be used as an index for the schizophrenogenic hereditary predisposition. As an example, the value of the genetic and statistical approach to the symbiontic psychoses is demonstrated. Conclusions for the concept of schizophrenialike psychoses are drawn.
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  • 26
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 6 (1972), S. 181-192 
    ISSN: 0020-7608
    Schlagwort(e): Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The problem of evaluating the radial electron-electron distribution function P0(r12) from the spin-free 2-particle density matrix P(2)(r1, r2Ir'1, r'2) is considered in detail. The analysis is first applied to 2-electron S-type functions built from l2 configurations. For the special case l = 0, the expression for P0(r12) reduces to the result obtained by Coulson and Neilson.For non-spherically symmetric states of N-electron atoms, the angular integrations are handled by a procedure used by Calais and Löwdin in their evaluation of atomic integrals containing functions of r12. Consideration is also given to the evaluation of necessary radial integrals.
    Zusätzliches Material: 2 Tab.
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  • 27
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 6 (1972) 
    ISSN: 0020-7608
    Schlagwort(e): Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
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  • 28
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 6 (1972), S. 281-287 
    ISSN: 0020-7608
    Schlagwort(e): Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: A simple semi-theoretical expression for β, the core resonance integral as used in the semi-empirical π-èlectron calculations has been proposed. β's for some standard C = C and C = 0 lengths have been evaluated with the proposed formula and the calculated values are compared with those obtained by other semi-theoretical and empirical methods. Electronic spectra of ethylene, formaldehyde, trans-butadiene and benzene have been calculated by a Pariser-Parr-like semi-empirical method with the values of β thus obtained. The calculated spectra are found to be in good agreement with the observed ones.
    Zusätzliches Material: 2 Tab.
    Materialart: Digitale Medien
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  • 29
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 6 (1972), S. 337-345 
    ISSN: 0020-7608
    Schlagwort(e): Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The variation perturbation method in the coupled Hartree-Fock (HF) scheme has been used to calculate the fourth-order energies of He, Li+ and Be2+ ions subjected to a uniform external electric field. The hyper-polarizabilities γh which are related to the fourthorder energies have been calculated neglecting intra-atomic correlation. For He the observed value is γh = 53.6 ± 4.0 a.u. The present estimate in the coupled and uncoupled HF schemes yield 36.2 and 45.3 a.u. respectively. The other calculations using correlated ground state wave function gave values in the range 42-44 a.u. The discrepancies between our result and those of others have been discussed.
    Zusätzliches Material: 2 Tab.
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  • 30
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 6 (1972), S. 383-386 
    ISSN: 0020-7608
    Schlagwort(e): Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: It is a standard theorem of group representation theory that the dimension of an irreducible representation is a divisor of the order of the group. This paper gives a new, relatively simple proof, intended to make the theorem understandable to readers unfamiliar with algebraic integers.
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  • 31
    ISSN: 0020-7608
    Schlagwort(e): Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Ground and excited singlet state dipole electric π polarizabilities of a set of conjugated molecules are calculated. Second order perturbation theory is used in the Epstein-Nesbet and Möller-Plesset versions. Hückel and SCF-LCAO-MO are used alternatively as a basis. The Möller-Plesset-SCF-LCAO-MO calculation appears well related to experimental values.
    Zusätzliches Material: 2 Tab.
    Materialart: Digitale Medien
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  • 32
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 6 (1972), S. 455-464 
    ISSN: 0020-7608
    Schlagwort(e): Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: A theory for using non-orthogonal radial orbitals between shells with identical orbital quantum numbers, in the case of complex configurations, is presented. Construction of the antisymmetric wave function of the whole configuration, with the help of antisymmetrical wave functions of individual shells, is described. General methods of calculating matrix elements of one- and two-electron operators are given.
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  • 33
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 6 (1972), S. 509-518 
    ISSN: 0020-7608
    Schlagwort(e): Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Diatomic integral formulas involving Slater-transform-Preuss functions are obtained for the Coulomb and hybrid types. One-center Coulomb integrals are also considered. All results have finite sums containing a one-dimensional numerical integration.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
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  • 34
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 6 (1972), S. 925-933 
    ISSN: 0020-7608
    Schlagwort(e): Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: It is shown how the irreducible representations of a finite group can be calculated from the irreducible characters (the latter can be calculated exactly by using Dixon's method). All elements of the matrix, representing a group element, lie in the rational field of polynomials of ξ = exp (2πi/e), where e is the exponent of the group.
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  • 35
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 6 (1972), S. 975-988 
    ISSN: 0020-7608
    Schlagwort(e): Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The quadrupole moment functions (molecular quadrupole moment versus internuclear distance) have been determined by quantum mechanical calculations for H2 (by Kolos and Wolniewicz), N2 (by Wahl and Nesbet), and CO (by Nesbet). These functions are used with numerical vibrational wave functions to compute matrix elements which are useful for calculations of scattering cross sections, energy transfer rates and excitation probabilities, and infrared intensities of forbidden bands.
    Zusätzliches Material: 9 Tab.
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  • 36
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 6 (1972), S. 327-336 
    ISSN: 0020-7608
    Schlagwort(e): Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The one-electron Hamiltonian method is developed to solve the variational equations of the MC SCF theory.The many-parameter family of the one-electron Hamiltonian is derived and conditions for parameters to provide convergence of the SCF procedure to the energy minimum are obtained. A computation scheme based on the use of the one-electron Hamiltonian is described.
    Zusätzliches Material: 10 Tab.
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  • 37
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 6 (1972), S. 367-382 
    ISSN: 0020-7608
    Schlagwort(e): Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The separated electron pair (SEP) model (strongly orthogonal geminals) and methods for its systematic extension have been applied to three different localization schemes for C≡O. The optimum SEP wave function is obtained for the particular localization scheme that involves three equivalent bent bonds. The major corrections to the SEP model arise from one-electron transfer terms. Two-electron transfer terms were important only for those pairs that were not well localized. It was found that the separate definitions of the total intrapair and interpair correlation energies did not depend strongly on the choice of localization scheme.
    Zusätzliches Material: 1 Ill.
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  • 38
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 6 (1972), S. 401-406 
    ISSN: 0020-7608
    Schlagwort(e): Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Ground state single determinant LCAO-MO-SCF wave functions, using a large contracted Gaussian basis set (6s, 2p, 1d/3s, 1p), have been computed for the 9 electron molecular systems of CH3 and NH3+. The minimum energies obtained using Roothaan's open shell SCF procedure for the planar equilibrium geometries were -39.5703 Hartree for CH3 and -55.8945 Hartree for NH3+. Additional properties such as electron populations and multiple moments were calculated from the planar wave functions.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
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  • 39
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 6 (1972), S. 449-453 
    ISSN: 0020-7608
    Schlagwort(e): Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: It is shown that under certain conditions the time-dependent Hamilton-Jacobi equation (TDHJE) is satisfied in the mean in quantum mechanics provided the classical action is replaced by Dirac's complex quantal action. This may be regarded as the equivalent of Ehrenfest's theorem for the TDHJE. Expectation values of operators are discussed in a similar manner.
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  • 40
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 6 (1972), S. 501-508 
    ISSN: 0020-7608
    Schlagwort(e): Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The ground state H—H+ and H—H interactions are used as model interactions for investigating the feasibility of using Gaussian basis sets for representing charge overlap effects in intermolecular forces. The non-expanded charge-induced dipole energy and the non-expanded dipole-dipole dispersion energy, respectively, for these interactions are calculated using two types of Gaussian basis functions to represent the first order wave function, Ψ(1). Very good results for these interaction energies, which include charge overlap effects, are obtained for all interatomic separations by using small Gaussian basis sets to represent the interaction, that is Ψ(1), and/or the isolated atoms (the zeroth order wave function).
    Zusätzliches Material: 5 Tab.
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  • 41
    ISSN: 0020-7608
    Schlagwort(e): Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The valence electron distributions of the hydrogen-bonded systems C4H4NH … NC5H5 formed from pyrrole and pyridine and C4H4N- … HNC5H+ from pyrrole anion and pyridinium ion have both been investigated using the charge iterative extended Hückel method. The results are presented in the form of contour diagrams showing the charge densities in pertinent sections of the hydrogen-bonded systems, and also in the corresponding parts of the non-interacting constituent molecules. The density differences between interacting and non-interacting systems brought about by hydrogen bonding are also presented. Like earlier investigated hydrogen bond types, an N—H … N bond is characterized by an increase of charge density in the covalent N—H bond, and a decrease at the acceptor atom. The formation of a rather low maximum in the centre of the H … N bond is also observed. The hydrogen bonding interaction causes a transfer of charge to the donor molecule of the same order of magnitude in both systems considered.
    Zusätzliches Material: 7 Ill.
    Materialart: Digitale Medien
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  • 42
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 6 (1972), S. 555-574 
    ISSN: 0020-7608
    Schlagwort(e): Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: A self-consistent perturbation theory is derived in the framework of Roothaan's MOLCAO procedure for closed shell systems. Contrary to previous investigations which have considered only one particle perturbations, two particle perturbation operators are considered. Expressions for the first-order density matrix and first- and second-order energy corrections are obtained. A diagram formulation of the complete perturbation expansion is presented.The results are applied to the treatment of the intermolecular interaction problem. The interaction energy is represented as a sum of several contributions: Coulomb, exchange, resonance, polarization and exchange repulsion. A semi-empirical version of the theory is suggested which explicitly involves all the physically significant energy terms and may be useful for the investigation of complex systems.
    Materialart: Digitale Medien
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  • 43
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 6 (1972), S. 609-611 
    ISSN: 0020-7608
    Schlagwort(e): Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The equivalence of the perturbation formalism, in the Rayleigh-Schrödinger frame-work, between secular and generalized secular equations is analysed.
    Materialart: Digitale Medien
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  • 44
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 6 (1972), S. 625-637 
    ISSN: 0020-7608
    Schlagwort(e): Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The electronic structure and preferred conformations of F3P·BH3 and F2HP·BH3 are investigated in the framework of the CNDO/2 approximation. In complete agreement with microwave data, the staggered conformations are predicted to be the most stable ones. The barriers to internal rotation are in good agreement with experimental values (F3P·BH3: calc. = 3.03 kcal/mole, exp. = 3.24 ± 0.15 kcal/mole; F2HP·BH3: calc. = 3.63 kcal/mole, exp. = 4.05 ± 0.45 kcal/mole) and a bicentric energy partitioning shows that the variations of the total energy are completely reflected by the only variation of the interaction energy between phosphorus and H atoms bonded to boron. The analysis of the electron densities reveals the importance of the 3s(P) → 2px(B) transfer in the formation of the co-ordination. Finally, the computed dipole moment value and direction agree with corresponding experimental data.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
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  • 45
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 6 (1972), S. 663-668 
    ISSN: 0020-7608
    Schlagwort(e): Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The diamagnetic susceptibility χ and magnetic shielding σ for H2+ are investigated in the range of internuclear separations R = 1.6 a.u. to R = 2.4 a.u. according to a previously reported technique. From this data values of 〈χ〉 and 〈σ〉, for which nuclear motion due to zero-point vibration and centrifugal stretching is taken into account, are calculated at 300°K. These averages are 〈χ〉 = -0.3902 α2ao3 and 〈σ〉 = 1.096 × 10-5 c.g.s. units which are approximately 3.1% and 1.4% respectively, smaller than the equilibrium values.
    Zusätzliches Material: 3 Tab.
    Materialart: Digitale Medien
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  • 46
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 6 (1972), S. 725-746 
    ISSN: 0020-7608
    Schlagwort(e): Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Tables of symmetrized powers of the irreducible representations of point groups are presented together with a derivation of the formula used to obtain them. It is shown how these tables may be applied to various quantum-chemical problems.
    Zusätzliches Material: 9 Tab.
    Materialart: Digitale Medien
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  • 47
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 6 (1972), S. 779-785 
    ISSN: 0020-7608
    Schlagwort(e): Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: By a proper approximation of the interaction term in a many-electron Hamiltonian the Hartree-Fock equations are decoupled. Making use of this simplification one obtains a good initial guess for the wave function with minimal computational work. Refining the procedure, the exact HF limit can be achieved. Total energies, ionization potentials and excitation energies for light atoms are calculated.
    Zusätzliches Material: 3 Tab.
    Materialart: Digitale Medien
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  • 48
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 6 (1972) 
    ISSN: 0020-7608
    Schlagwort(e): Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 49
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 6 (1972), S. 57-81 
    ISSN: 0020-7608
    Schlagwort(e): Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The molecular-electronic structure of the metal phthalocyanines (Fe, Co, Ni and Cu) has been determined by the molecular orbital treatment. Coulomb integrals of the metal atom occurring in the secular determinants have been approximated equivalent to the valence state ionization energy (VSIE) of a metal orbital for a particular charge configuration. The calculated π-electron charge densities have been found to be higher on the nitrogen atoms as compared to the other atoms in the molecule. This is in agreement with the e.s.r. studies of the metal phthalocyanines. To test the correctness of the molecular orbital calculations, the π-π* transitions (14,000 cm-1 - 30000 cm-1), d-d* transitions (20000 cm-1 - 60000 cm-1) and charge transfer transitions (15000 cm -1 - 30000 cm-1) have been calculated in the metal phthalocyanine molecules. The calculated frequencies have been compared with the observed ones and found in fair agreement.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
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  • 50
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 6 (1972), S. 101-123 
    ISSN: 0020-7608
    Schlagwort(e): Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: An exact cluster expansion of many electron wave functions is derived, beginning with a finite linear combination of Slater determinants rather than the more usual single determinant. This general cluster expansion is found to apply both in the case where all possible Slater determinants from a finite set of spin orbitals are included in the linear combination, and in the case where the number of determinants is restricted.The special properties of that finite linear combination of determinants closest to the exact wave function in the least squares sense are studied. These properties lead to the derivation of a general correlated wave functions method, illustrating again the close relationship between methods of this type and cluster expansion theory. Additional approximations, necessary for practical calculations, are set out.
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  • 51
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 6 (1972), S. 155-166 
    ISSN: 0020-7608
    Schlagwort(e): Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: A first order perturbation treatment starting with SCF-MO'S in canonical or equivalent quasi-localized form is presented for the hyperfine coupling constants of vinyl and methyl radicals. The spin-polarisation contribution to hyperfine splittings is found to be large, negative for the proton of the radical center in both radicals and positive for the β protons of vinyl.
    Zusätzliches Material: 5 Tab.
    Materialart: Digitale Medien
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  • 52
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 6 (1972), S. 593-596 
    ISSN: 0020-7608
    Schlagwort(e): Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Zusätzliches Material: 2 Tab.
    Materialart: Digitale Medien
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  • 53
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 6 (1972) 
    ISSN: 0020-7608
    Schlagwort(e): Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
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  • 54
    ISSN: 0020-7608
    Schlagwort(e): Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: A general formalism is set up to apply the variation-perturbation method to the quantum theory of non-linear optical effects, in particular to the electric and magnetic birefringence (Kerr and Cotton-Mouton effects).The quantities describing these effects are obtained from the wave function Ψ0(0) of the ground state of the unperturbed molecule and the different vectors and tensors which are determined by a variation method.With this method an approximate computation of the Kerr and Cotton-Mouton constants of some simple molecules has been made.
    Zusätzliches Material: 5 Tab.
    Materialart: Digitale Medien
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  • 55
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 6 (1972), S. 93-100 
    ISSN: 0020-7608
    Schlagwort(e): Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: It is shown that under certain restrictions the system of determinants ϕi(x1)ϕk(x2) - ϕk(x1)ψi(x2) constructed from two different sets of orbitals ψk and ϕk will be the complete set of functions for antisymmetrical two-electron wave functions if the condition i 〈 k is imposed.
    Materialart: Digitale Medien
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  • 56
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 6 (1972), S. 143-153 
    ISSN: 0020-7608
    Schlagwort(e): Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The Green's functions for the simplest quantum mechanical systems the linear harmonic oscillator, the three-dimensional isotropic oscillator, the Morse oscillator, the Kratcer potential, and the double-minimum potential V(x) = (mw2/2)(/x/-R)2 are presented in closed analytical forms.
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  • 57
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 6 (1972), S. 193-196 
    ISSN: 0020-7608
    Schlagwort(e): Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Zusätzliches Material: 2 Tab.
    Materialart: Digitale Medien
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  • 58
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 6 (1972), S. 201-209 
    ISSN: 0020-7608
    Schlagwort(e): Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: A one center method, based on the work of Karplus and Kolker, is discussed and used to calculate the induction energy, through O(R-8), for the H(ls) - H+ interaction employing two types of Gaussian basis sets constructed from functions of the form {rje-αr2}. The effective hydrogen atom excitation energies and transition multipole moment matrix elements generated in these calculations are used to calculate the dispersion energy for the H(ls) - H(ls) interaction, through O(R-10), and the R-9 triple dipole energy corresponding to the interaction of three H(ls) atoms. The results indicate that Gaussian functions can form good basis sets for obtaining long range forces for a variety of multipole interaction energies.
    Zusätzliches Material: 5 Tab.
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  • 59
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 6 (1972), S. 263-269 
    ISSN: 0020-7608
    Schlagwort(e): Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The paramagnetic properties of one-dimensional macromolecules with conjugated C=C bonds are discussed on the basis of low-lying quasi-homeopolar triplet excitations. A good agreement with the experimental results is shown.
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  • 60
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 6 (1972), S. 289-296 
    ISSN: 0020-7608
    Schlagwort(e): Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The matrices of the irreducible representations of the 3-dimensional rotation group are shown to be related to Krawtchouk's orthogonal polynomials of a discrete variable x = j - m', whose degrees are given by n = j + m. The relation follows directly from the recurrence formulas satisfied by the matrix elements and permits a concise development of the formal properties of the rotation matrices. In particular, an asymptotic relation for large j is developed that generalizes a formula first discussed for a special case by Wigner.
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  • 61
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 6 (1972) 
    ISSN: 0020-7608
    Schlagwort(e): Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
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  • 62
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 6 (1972), S. 23-45 
    ISSN: 0020-7608
    Schlagwort(e): Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: In order to treat the interaction energy of two molecules a standard Rayleigh-Schrödinger perturbation theory is developed. The Hartree-Fock functions of the separated molecules are used as one particle basis functions, the initial set of states being truncated and non-orthogonal. The non-orthogonality is included into the Hamiltonian by orthogonalization of the basis set. The unperturbed Hamiltonian is chosen so that it possesses the correct symmetry properties with respect to the electron permutations between different molecules. The procedure of this kind automatically results in the appearance of charge transfer states.A graphical technique is elaborated which is a modified version of the Feynman-Goldstone technique and provides a convenient representation of the interaction energy contributions of any order. As an example the first- and the second-order diagrams are considered.A correct expression for the dispersion energy is obtained which differs by a factor from that of the theory using a nonsymmetrical zero approximation.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
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  • 63
    ISSN: 0020-7608
    Schlagwort(e): Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Group-theoretical methods for determining permitted terms of electrons in polyatomic molecules and complexes in the MO and HL methods are proposed. Essentially, the permutational symmetry of the electron system is utilized. Some concrete examples of the operation of these methods are considered.
    Zusätzliches Material: 2 Ill.
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  • 64
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 6 (1972), S. 131-142 
    ISSN: 0020-7608
    Schlagwort(e): Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Two different perturbation series (the polarization expansion and a united-atom expansion) of the ground state energy of the delta-function model for one-electron diatoms are studied and the radii of convergence are determined. For both expansions the singularity in the energy which limits the radius of convergence is a branch point with exponent one-half. The physical significance of the branch point is that for particular values of the perturbation parameter, two different energy eigenvalues coalesce. The positions of the branch points are computed as a function of the internuclear separation R. For all values of R, both series converge for all physical values of the perturbation parameters. A lower bound to the radius of convergence of the polarization expansion has been computed previously by Claverie. It is proved in the present paper that the lower bound calculation is in fact an exact determination of the radius of convergence. The results of the model study are applied to real one-electron diatoms to suggest the possible location of a branch point singularity in the energy of the ground state.
    Zusätzliches Material: 3 Ill.
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  • 65
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 6 (1972), S. 197-198 
    ISSN: 0020-7608
    Schlagwort(e): Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
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  • 66
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 6 (1972), S. 271-279 
    ISSN: 0020-7608
    Schlagwort(e): Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Previous mathematical proofs of the non-crossing rule concerning the potential energy curves of a diatomic molecule are examined and criticised. A new treatment is presented which is simple and mathematically rigorous.
    Materialart: Digitale Medien
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  • 67
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 6 (1972), S. 313-325 
    ISSN: 0020-7608
    Schlagwort(e): Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The phenomenon of nuclear quadrupole resonance is presented from the grouptheoretical point of view. This approach allows one to discuss the splitting of the nuclear spin states without prior wave-mechanical calculation. Nuclear quadrupole moments are also compared with moecular quadrupole moments and the differences discussed. Finally the selection rules are deduced.
    Zusätzliches Material: 3 Ill.
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  • 68
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 6 (1972), S. 353-366 
    ISSN: 0020-7608
    Schlagwort(e): Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: A new expression is given for the electron repulsion integral over Slater-type orbitals on four different centers. It is based on the asymptotic expansion derived from the bipolar expansion of a previous paper. The expression has the form \documentclass{article}\pagestyle{empty}\begin{document}$$ I\,\mathop \sim \,\sum \limits_{q_1 }^\infty \mathop \sum \limits_{q_2 }^\infty \,F_{q_1 q_2 } (R_{{\rm PQ}})\sigma _{q_1 } (A,\,B)\sigma _{q_2 } (C,\,D) $$\end{document} where qp = {np, lp, mp}. Both F and σ are closed expressions. The quantity F is a combination of incomplete gamma functions, Laguerre polynomials and spherical harmonics. It depends upon the relative coordinates of a point P on the AB axis and a point Q on the CD axis. The functions σnlm(A, B) depend on the charge distribution (χAχB); they have the character of overlap integrals and are of the form \documentclass{article}\pagestyle{empty}\begin{document}$$ \sigma _{nlm} (A,\,B)\, = \,\mathop \Sigma \limits_v \,\mathop \Sigma \limits_w \,F_{vw} (\zeta _A R_{AB},\,\zeta _B R_{AB})K_{vw} (R_{AB}) $$\end{document}
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
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  • 69
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 6 (1972), S. 387-399 
    ISSN: 0020-7608
    Schlagwort(e): Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: SCF-LCAO-MO-CI semi-empirical π-electron calculations have been made of the first two singlet transitions and ionization potentials of hydroxy-, methyl- and hydroxy-methyl substituted p-benzoquinone, using a modified Pariser-Parr-Pople method. The various molecules could be divided into two classes on the basis of their first π-electron transition, namely, those in which the 3-position was occupied and others where this position was vacant.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
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  • 70
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 6 (1972), S. 519-523 
    ISSN: 0020-7608
    Schlagwort(e): Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Attention is called to the attractive cusp conditions as useful constraints in fixing the elements of the electron density matrix. An equation for determination of pure state densities satisfying arbitrary constraints is reviewed, and a detailed formalism for using cusp conditions with this equation is displayed. A calculation is done using the nitrogen molecule as an example.
    Zusätzliches Material: 1 Tab.
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  • 71
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 6 (1972), S. 211-224 
    ISSN: 0020-7608
    Schlagwort(e): Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: A variational formulation of the Hartree-Fock-Roothaan (HFR) theory for open shell ions in presence of time dependent perturbations is presented. The theory has been used to calculate the dynamic polarizabilities of the first three ions of the Li sequence. The polarizability values, extrapolated to zero frequency, show good shell by shell agreement with the corresponding static results. The polarizability graphs display resonance behaviour at the transition frequencies of the ions, and a study of these points leads to analytic HF wave functions for their low lying excited states. The calculated transition frequencies are in excellent accord with the experimental values. The calculated oscillator strengths for the 2s → np transitions are in reasonable agreement with the extensive multiconfiguration calculations of Weiss and the available experimental results.
    Zusätzliches Material: 1 Ill.
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  • 72
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 6 (1972), S. 225-261 
    ISSN: 0020-7608
    Schlagwort(e): Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Hougen has established, for quasi-rigid molecules, the relationship between permutationinversions acting on the molecular Hamiltonians written in Cartesian co-ordinates and permutation-rotations (perrotations) of symmetry acting on nuclear equilibrium configurations. We extend these relations to the case of non-rigid molecules. For this, we introduce kinetic perrotations which act on nuclear equilibrium configurations in the same way as do Altmann's isodynamic operators. We show that isodynamic operators do not always form a group. Moreover, their action cannot be extended to the electrons. They cannot be used for the classification of molecular wave functions. This classification is achieved by using the group of Longuet-Higgins and the group of the corresponding feasible perrotations.
    Zusätzliches Material: 9 Ill.
    Materialart: Digitale Medien
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  • 73
    ISSN: 0020-7608
    Schlagwort(e): Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: A separated pair calculation of the electronic structure of the Li2O molecule is described. Rather extensive calculations were made of the potential surface for symmetric configurations of Li2O using a double zeta Slater orbital basis. A linear configuration with LiO bond length of 1.71 Å is found to be most stable. The electron distribution and correlation effects are discussed.
    Zusätzliches Material: 7 Ill.
    Materialart: Digitale Medien
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  • 74
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 6 (1972), S. 347-352 
    ISSN: 0020-7608
    Schlagwort(e): Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: An expansion is given for the inverse interelectronic distance in terms of the coordinates of the two electrons. The terms in the expansion contain the coordinates of the first electron with respect to two centers A, B and those of the second electron with respect to two centers C, D.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
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  • 75
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 6 (1972) 
    ISSN: 0020-7608
    Schlagwort(e): Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 76
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 6 (1972), S. 413-438 
    ISSN: 0020-7608
    Schlagwort(e): Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The one-electron integral over Slater-type atomic orbitals centered at A and B and irregular solid spherical harmonics as operator centered at C is evaluated analytically by using elliptical coordinates and translation of the solid spherical harmonics from center C to either focus A or B. A special case is the three-center nuclear attraction integral which is also evaluated by means of the Neumann expansion and expressed without associate Legendre functions of the second kind. The strict observation of the charge distribution concept leads to compact expressions for the integral. It has the further advantage that the charge density distributions which have been developed for the two-center cases and used in calculations for diatomic molecules can be utilized.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
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  • 77
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 6 (1972), S. 47-55 
    ISSN: 0020-7608
    Schlagwort(e): Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: π-electron SCF-MO theory in its variable electronegativity formalism has been applied to some monosubstituted benzenes. Calculated charge densities and bond orders for the ground and the first excited electronic states are correlated with chemical reactivity and the changes in molecular geometry on electronic excitation. The calculated results for spectra are compared with those obtained using the PPP method and also with the available experimental data.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
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  • 78
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 6 (1972), S. 596-597 
    ISSN: 0020-7608
    Schlagwort(e): Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
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  • 79
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 6 (1972), S. 599-599 
    ISSN: 0020-7608
    Schlagwort(e): Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 80
    ISSN: 0020-7608
    Schlagwort(e): Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Wave functions for impurities or local complexes in crystals are usually described within one of the two popular schemes furnished by the MO and the HL methods. The purpose of the present note is to draw attention to a set of tables which allow a translation between these two descriptions.
    Materialart: Digitale Medien
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  • 81
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 6 (1972), S. 647-650 
    ISSN: 0020-7608
    Schlagwort(e): Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The corresponding orbital energy expression of Lefebvre and Prat [1] has been developed and used to obtain some extended Hartree-Fock results for Lithium Hydride.
    Zusätzliches Material: 1 Tab.
    Materialart: Digitale Medien
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  • 82
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 6 (1972), S. 669-680 
    ISSN: 0020-7608
    Schlagwort(e): Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: A computational method for calculating quadrupole moments from molecular wave functions in a Slater orbital basis set is described. Using both IEHT and CNDO wave functions quadrupole moments for a series of polyatomic molecules are calculated. They are compared with experimental results and the IEHT wave functions are found to give agreement with experiment while CNDO wave functions do not. The importance of bicentric densities (overlap densities) in the calculation of multipole moments is shown. This is followed by a discussion of the usefulness of these wave functions for a quantitative characterization of the electronic structure of large molecules.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
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  • 83
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 6 (1972), S. 761-777 
    ISSN: 0020-7608
    Schlagwort(e): Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The application of the representation theory of symmetric groups to the solution of quantum chemical problems is discussed. This is done using matrices which do not represent Sn in the normal sense, but which are much simpler to calculate than the Yamanouchi-Kotani representation. A complete discussion of the calculation of these matrices is given.
    Zusätzliches Material: 1 Ill.
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  • 84
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 6 (1972), S. 793-795 
    ISSN: 0020-7608
    Schlagwort(e): Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
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  • 85
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 6 (1972), S. 799-799 
    ISSN: 0020-7608
    Schlagwort(e): Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 86
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 6 (1972), S. 849-858 
    ISSN: 0020-7608
    Schlagwort(e): Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: A quasi-relativistic approach to the MO-LCAO method is formulated taking into account the relativistic effects with an accuracy up to (v/c)2 terms, the relativistic part of the electronic interaction in the Hamiltonian being neglected. In the framework of this approximation a set of SCF equations of the Roothaan form is derived; here only the relativistic analogue to the closed shell systems with one-determinant wave functions is considered. In so doing three types of relativistic corrections arise which are quite similar to those of the Pauli equation for one-electron atoms. The new matrix elements appearing due to these corrections can be reduced to some common integrals, which have to be calculated with relativistic radial atomic functions. The method allows a semi-empirical approach to the problem and does not require the Dirac four-component atomic functions (unknown in the most cases), thus making possible approximate quasi-relativistic electronic structure calculations of heavy-atom compounds.
    Materialart: Digitale Medien
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  • 87
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 6 (1972), S. 911-917 
    ISSN: 0020-7608
    Schlagwort(e): Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The Schrödinger equation for the hydrogen molecular ion is written as a perturbed united atom which is then treated as a generalized eigenvalue equation. The ground state energy is calculated through third order for small internuclear distances.
    Zusätzliches Material: 1 Tab.
    Materialart: Digitale Medien
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  • 88
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 6 (1972), S. 949-966 
    ISSN: 0020-7608
    Schlagwort(e): Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Closed form one centre partial wave perturbation results are obtained through second order in the energy for H2+-like molecules with arbitrary nuclear charges. The expansion centre for the method is taken at an arbitrary point along the internuclear axis and the zeroth-order wave function is a screened “1s” function centred at the expansion point. Various fixed one centre calculations of other workers for the lsσ states of H2+ and HeH++ and for the 2pσ state of HeH++ are generated as limiting cases of this more general treatment. The floating one centre perturbation results for the 1sσ states of H2+ and HeH++ are used as models for discussing the usefulness of allowing the expansion centre in the one centre method to be a function of nuclear configuration.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
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  • 89
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 6 (1972), S. 617-623 
    ISSN: 0020-7608
    Schlagwort(e): Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: An economic algorithm for storing and processing two-electron integrals arising in LCAO-MO calculations is presented. The integrals are sorted prior to the SCF iterative scheme, classified according to equivalences in the orbital indices and finally stored on separate files that contain only integrals of one type. The novel approach of physically separating the integrals according to category is shown to be more efficient than random storage. Actual computing times for the new technique are tabulated for a representative number of molecular systems and compared with times obtained using previously reported methods.
    Zusätzliches Material: 1 Tab.
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  • 90
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 6 (1972), S. 651-661 
    ISSN: 0020-7608
    Schlagwort(e): Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: A variation-perturbation method, analogous to a technique devised by Das and Bersohn for the study of the hydrogen molecule, is developed for calculation of the diamagnetic susceptibility χ and magnetic shielding σ and is applied to a study of the hydrogen molecule ion. Two approximations are investigated-in a first approximation, χ = -0.37814α2ao3 and σ = 1.112 × 10-5 c.g.s. units and in a second approximation, χ = -0.37569α2ao3 and σ = 1.128 × 10-5 c.g.s. units.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
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  • 91
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 6 (1972), S. 681-700 
    ISSN: 0020-7608
    Schlagwort(e): Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Canonical transformations have been widely used to simplify Hamiltonians and other operators. In molecular and in solid state theory, the so-called Van Vieck expansion is usually employed for this purpose while in theories of particles interacting with fields a combination of canonical transformations in closed form with Van Vleck type expansions has been found effective. For some of the transformations used in applications formulas in closed form are well known. It will be shown here that such formulas can be derived whenever the transformation function is bilinear in the canonical variables, and further that the use of matrix operators makes it possible to simplify these derivations substantially. The Cayley-Hamilton theorem is then used to express the expansions for the matrix operators in closed form. The number of separate operator terms appearing in the formulas thus obtained is the same as the rank of the matrices used. To calculate the coefficients of these operator terms a new type of special functions is introduced. The resulting linear canonical transformations include generalized rotations in both ordinary and phase-space. Explicit results have been obtained for several two- to four-dimensional problems.
    Materialart: Digitale Medien
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  • 92
    ISSN: 0020-7608
    Schlagwort(e): Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: First-order wave functions and binding energies of the 1sσg and 2pσu states of H2+ are calculated by simple methods for internuclear separations between 0.2 and 10a0. An exact perturbation treatment of the lsσg state with a zeroth-order function of the form N exp (-sRλ/2) exp (sR μ2) yields only fair results. An alternative method starts with zeroth-order functions of the form N exp (-sRλ/2)[exp (-sRμ/2) ± exp (sRμ/2)] for the 1sσg and 2pσu states, respectively. An approximate first-order trial function is set up and the energies are determined variationally. For both states the results are comparable to those obtained by exact perturbation treatments of the same order.
    Zusätzliches Material: 4 Tab.
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  • 93
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 6 (1972), S. 795-797 
    ISSN: 0020-7608
    Schlagwort(e): Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
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  • 94
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 6 (1972), S. 843-847 
    ISSN: 0020-7608
    Schlagwort(e): Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The procedure proposed by Silverstone and others to modify virtual levels in SCF theory is extended as a technique to be used in any type of generalized secular equations. Some useful results are obtained.
    Materialart: Digitale Medien
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  • 95
    ISSN: 0020-7608
    Schlagwort(e): Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The electron density and spatial correlation as given by the MO, VB and AMO methods for H2 and H6 are studied by means of diagrams. For comparison, diagrams representing accurate wave functions for H2 are also given. The study of model functions representing localized bonds leads to results concerning the nature of localized electron pairs in agreement with those of Lennard-Jones.
    Zusätzliches Material: 9 Ill.
    Materialart: Digitale Medien
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  • 96
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 6 (1972), S. 439-448 
    ISSN: 0020-7608
    Schlagwort(e): Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Trial wave functions, written as the sum of a configuration interaction expansion and an explicitly correlated term which is not antisymmetric, are proposed for use in calculating the electronic properties of atoms and molecules. A variational principle, modified to allow the use for such partially antisymmetric wave functions, is developed. It is shown that the consequences of partial antisymmetry on calculated expectation values can be estimated. The method avoids difficult three-electron integrals which arise in other theories.
    Materialart: Digitale Medien
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  • 97
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 6 (1972), S. 473-489 
    ISSN: 0020-7608
    Schlagwort(e): Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The analysis of the equations of the unrestricted Hartree-Fock (UHF) method for polyenes CNHN+2 with even and odd N » 1 is carried out. The equations of the UHF method are shown to be the same in both cases. The comparison of the UHF method with the extended Hartree-Fock (EHF) method applied to large systems is performed. The ground state and π-electron spectra of long cumulene chains CNH4 are treated by the EHF Method. The end effects are taken into consideration. It is shown that the EHF method gives a finite value of the first optical transition frequency and, at the same time, zero value of torsion barrier of end CH2-groups in long cumulene chains (N → ) in contrast to previous calculations of cumulenes by the Huckel method and the restricted Hartree-Fock method.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
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  • 98
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 6 (1972), S. 525-539 
    ISSN: 0020-7608
    Schlagwort(e): Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The valency state (vs) concept is analyzed in the Hartree-Fock approximation. A valency state “standard” is defined for atoms at infinite separation. A molecular orbital valency state (Movs) is defined from a partitioning technique (bond energy analysis) previously introduced for the Hartree-Fock molecular wave functions. The Movs for a given atom in a molecule is much higher in energy than the vs and its energy varies from molecule to molecule depending on the exact field of the surrounding atoms. The examples selected in the discussion are the CH4 CH3F, CH2F2, CHF3 and CF4 molecules.An analysis of the orbital energies is then given in terms of the bond energy. The importance of the rearrangement effects following ionization of inner shell electrons (simulation of ESCA type experiments) is illustrated with computations of the positive ion for methane and its fluoroderivatives. It is concluded that rearrangement following ionization from inner shells is as important as rearrangements following ionization from valency electrons. A direct consequence is that the orbital energies should not be equated to the inner shell ionization potentials. The computation of such ionization potentials agrees to about 99.5% with ESCA data, when the energy of both the neutral and ionic species are computed; the use of the orbital energies limits this agreement to about 95%.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
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  • 99
    ISSN: 0020-7608
    Schlagwort(e): Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Modern techniques for multidimensional numerical integration, Korobov's and Sobol's formulas namely, are used for the direct computation of matrix elements between the localized molecular orbitals needed for a configuration interaction calculation by a perturbation method. A minimal orbital basis of Slater functions is used for formaldehyde and ethylene taken as example. The resulting precision is satisfactory.
    Zusätzliches Material: 5 Tab.
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  • 100
    ISSN: 0020-7608
    Schlagwort(e): Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: A method is presented which leads to accurate Fourier transform values of any 1s-1s Slater-type orbital overlap distribution. The numerical merits are discussed and illustrated by some examples.
    Zusätzliches Material: 1 Tab.
    Materialart: Digitale Medien
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