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  • Digitale Medien  (2.409)
  • 1970-1974  (2.409)
  • 1965-1969
  • 1890-1899
  • 1972  (2.409)
  • General Chemistry  (1.021)
  • Organic Chemistry  (646)
  • Physics  (555)
  • Computational Chemistry and Molecular Modeling  (92)
  • Physical Chemistry  (61)
  • Electron Microscopy
Materialart
  • Digitale Medien  (2.409)
Erscheinungszeitraum
  • 1970-1974  (2.409)
  • 1965-1969
  • 1890-1899
Jahr
Schlagwörter
  • 1
    Digitale Medien
    Digitale Medien
    Springer
    Journal of neurology 202 (1972), S. 229-240 
    ISSN: 1432-1459
    Schlagwort(e): Cerebrospinal Fluid ; Plasmacytoma (IgA) ; Cytodiagnosis ; Immunofluorescence ; Electron Microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung Bei einem 37jährigen Patienten mit IgA-Plasmocytom zeigte sich während der zweiten Phase der Krankheit, die mit schweren cerebralen Symptomen und Hirnnervenausfällen verlief, eine ausgeprägte Pleocytose im Lumballiquor. Etwa 50–60% der Liquorzellen waren cytologisch und elektronenoptisch teils als reife, ganz überwiegend jedoch als entdifferenzierte Plasmocyten, das heißt als Myelom-Zellen, zu deuten. Übereinstimmend zum immunelektrophoretischen und quantitativen Befund von vermehrtem IgA-Paraprotein und Bence-Jones-Protein im Liquor ließ sich in den meisten Blastomzellen eine entsprechende spezifische Immunfluorescenz nachweisen. Das Auftreten von Myelom-Zellen im Liquor ist unseres Wissens noch nicht beschrieben worden und erklärt sich hier aus der (autoptisch bestätigten) leptomeningealen Lokalisation des Plasmocytoms. In solchen Fällen kann der liquorcytologische Befund die Diagnose entscheiden.
    Notizen: Summary A 37-year-old male patient with monoclonal IgA dysproteinemia, severe brain symptoms and cranial nerve disturbances failed to show typical plasmacytoma findings in skull, bones, blood, bone marrow, spleen and lymphatic system. During a second recurrence of his illness a marked pleocytosis of the CSF was observed. 50 to 60% of the cells were classified cytologically and by electron microscopy as blastomatous plasmocytes, i.e. myeloma cells. Specific intracytoplasmatic immunofluorescence corresponded to the presence of IgA and Bence Jones paraprotein which was demonstrated in CSF by immunoelectrophoresis and immunodiffusion. Myeloma cells of CSF have never been described before. Autopsy of this case revealed an unusual type of plasmacytoma which involved the cerebrospinal leptomeninges and subarachnoid spaces mainly. The diagnosis in patients with this disease may be established for sure by the specific cytologic evaluation of the CSF.
    Materialart: Digitale Medien
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  • 2
    Digitale Medien
    Digitale Medien
    Springer
    Research in experimental medicine 158 (1972), S. 129-151 
    ISSN: 1433-8580
    Schlagwort(e): Preservation ; Porcine Liver ; Hypothermia ; Electron Microscopy ; Lysosomes ; Konservierung ; Schweineleber ; Hypothermie ; Elektronenmikroskopie ; Lysosomen
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung 6 Schweinelebern wurden durch einfache Unterkühlung 24 Std konserviert und die Strukturerhaltung in verschiedenen Zeitintervallen elektronenmikroskopisch und enzymcytochemisch untersucht. Für die initiale hypotherme Kurzzeitperfusion diente eine mit Kalium und Glucose angereicherte modifizierte Ringer-Lösung, der bei 3 Lebern zusätzlich sog. Zellstabilisatoren (Chlorpromazin und Prednisolon) hinzugefügt worden waren. Schwerwiegende Schädigungen der Ultrastruktur in den Hepatocyten, wie Desorganisation, Fragmentation, Vesikulation und Degranulation des endoplasmatischen Reticulums, Mitochondrienschwellung vom Matrix-Typ, Verklumpung und Margination des Chromatins sowie Rupturen der Zellmembran mit Austritt von Cytoplasmabestandteilen und Kernen in die Disséschen Räume und Sinusoidlichtungen traten vereinzelt nach 6–9stündiger, in der Mehrzahl der Zellen jedoch erst nach 12stündiger Konservierung auf. Die Lysosomen blieben über 18 Std unverändert. Bemerkenswert waren früh einsetzende regressive Veränderungen in den Kupfferschen Sternzellen, die schon nach 6 Std vielfach zu Cytolysen führten. Der Zusatz von Chlorpromazin und Prednisolon zur Perfusionslösung blieb ohne morphologisch erfaßbaren Effekt auf die Erhaltung der Ultrastruktur.
    Notizen: Summary 6 porcine livers were preserved by simple hypothermia for 24 hrs. Ultrastructural alterations were studied at various intervals with electron microscopic and enzyme cytochemical methods. A modified Ringer's solution with increased concentrations of potassium and glucose was used for initial hypothermic shorttime perfusion. In 3 of 6 cases cell stabilizers (chlorpromazine and prednisolone) were added to the perfusate. Severe ultrastructural changes such as disorganization, fragmentation, vesiculation, and degranulation of endoplasmic reticulum, swelling of the matrix in mitochondria, aggregation, and margination of chromatin as well as rupture of the plasma membrane followed by the release of cellular constituents into the Dissé spaces and the sinusoids appeared in several liver cells after 6–9 hrs of preservation. In a significant number of cells, however, they were observed only after 12 hrs of preservation. In lysosomes there were no changes for more than 18 hrs of preservation. Especially interesting were early regressive alterations of Kupffer cells leading frequently to cytolysis already after 6 hrs of preservation. The addition of chlorpromazine and prednisolone to the perfusate had no effect on the preservation of ultrastructure.
    Materialart: Digitale Medien
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  • 3
    ISSN: 1432-0533
    Schlagwort(e): Schizophrenia ; Disturbance of Metabolism in the Neuron ; Electron Microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Biopsies of a frontal gyrus from both schizophrenic and non-schizophrenic brains were examined by electron microscopy. The results in the schizophrenic brains are as follows: 1. Within the cytoplasm of the nerve cell, the Golgi apparatus was remarkably prominent. 2. Membranous structures, consisting of numerous interconnected tubules were observed in the nerve fibres. Abnormal structures appeared in the synapses and in many synapses vesicles were not observed. 3. Granular and vesicular material accumulated in large amount in the axon-oligodendroglial interface of myelinated nerve fibres: the material was gradually transferred from the axon-oligodendroglial interface to the inner mesoaxon and the outer layers of the myelin sheaths destroying some of the myelin sheaths. Mainly myelinated nerve fibres of medium size were involved. 4. A large amount of lipofuscin-like material was observed in the cytoplasm and the processes of the oligodendroglia. 5. Only the neuron and the oligodendroglia showed specific changes. Among the findings mentioned above, (3) was thought to be specific and originated from the disturbance of the metabolism of the neuron, due probably to some enzyme disturbance in the neuron.
    Materialart: Digitale Medien
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  • 4
    Digitale Medien
    Digitale Medien
    Springer
    Acta neuropathologica 20 (1972), S. 139-149 
    ISSN: 1432-0533
    Schlagwort(e): Perineurium ; Experimental Allergic Neuritis ; Extravasated Protein ; Electron Microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Electron microscopic observations on the perineurium in EAN are described. Extravasated serum protein was observed in the endoneurial space and also between the cellular laminae of the perineurium. A mechanism of macropinocytotic transport of protein across the perineurium is proposed. The observations are related to the known properties of the perineurium as a diffusion barrier and are interpreted as a mechanism by the perineurium to restore the composition of the endoneurial fluid.
    Materialart: Digitale Medien
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  • 5
    Digitale Medien
    Digitale Medien
    Springer
    Acta neuropathologica 20 (1972), S. 299-315 
    ISSN: 1432-0533
    Schlagwort(e): Cerebrospinal Angiopathy ; Pig ; Arterial Lesions ; Blood-Brain Barrier ; Electron Microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary An electron microscope study of the central nervous system was performed in 5 pigs with cerebrospinal angiopathy. Characteristic lesions in arterioles and small arteries are insudations and necroses in the media with the endothelial cell layer essentially intact. Some smooth muscle cells within the insudate may show transformation into fibroblast-like cells. Due to the proliferation of these cells a new subendothelial cell layer is formed. In venules there are marked plasmarrhagias although the endothelium appears to be normal and the number of pinocytotic vesicles does not increase. In collagen fibrils the cross striation appears unaltered; the diameter of the fibrils varies between 0.05–0.4 μm. Swollen astrocytes around vessels and in the neuropil contain large numbers of osmiophilic spherical or polyhedrical coacervations in their cytoplasm mostly without a limiting membrane. These cytoplasmic inclusions most likely represent blood plasma constituents which may have penetrated from the perivascular space of arterioles and venules into the astrocytes. The morphological substrate of the blood-brain-barrier at the capillary level is altered only rarely. As the cause of porcine cerebrospinal angiopathy, toxins of E. coli are discussed.
    Materialart: Digitale Medien
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  • 6
    Digitale Medien
    Digitale Medien
    Springer
    Acta neuropathologica 22 (1972), S. 145-157 
    ISSN: 1432-0533
    Schlagwort(e): Colchicine ; Astroglia ; Oligodendroglia ; Drug-Induced Changes ; Glial Cells ; Electron Microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Rabbits treated with a single intracisternal injection of 100 μg colchicine dissolved in 50 μl water, got signs of neurological disturbances within a day and became quadriparetic in about two days. The glial cells in the brain, the brain stem and spinal cord were examined. Special emphasis was paid to those in the hypoglossal and dorsal vagal nuclei. Many of the astrocytes became hypertrophic after injection of colchicine and got an increased number of filaments and cell organelles, including mitochondria and dense bodies. The oligodendrocytes showed more or less marked changes, including lipid droplets and dense bodies. Several glial cells, rarely noticed in the controls, showed marked signs of reactive changes and did not fulfil the criteria for either astrocytes or oligodendrocytes. The results obtained are discussed in relation to those obtained after other types of treatment of nervous tissue. It is concluded that the glial changes are partly due to effects induced by colchicine, which inhibits the intracellular transport, but not the formation of cell constituents. Emphasis had to be paid to the fact that drug-induced changes in the glial cells may severely alter the metabolism and function of adjacent neurons.
    Materialart: Digitale Medien
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  • 7
    ISSN: 1432-0533
    Schlagwort(e): Herpes Virus, Type 2 ; Tissue Culture ; Intranuclear Tubules ; Microtubular Structures ; Electron Microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Mature explants of mouse spinal cord and ganglia have been infected with Herpes virus hominis type 2. After 48 h, a high titer of virus was detected in the explant and typical herpes-like particles were seen by electron microscopy. They were more numerous in sensory neurons and Schwann cells than in the CNS possibly because of a more rapid propagation through the extracellular space in spinal ganglia. In the infected nuclei, besides the naked particles, numerous tubular formations were found, apparently resulting from virus infection and specific for herpes type 2. Their dimensions and fine structure are illustrated and compared to other microtubular formations. In the cytoplasm of theneurons, a dramatic disorganisation occurred and, in the Schwann cell, the plasma membrane underwent disruption. Consequently, the normal axon — Schwann cell intimate contact was lost.
    Materialart: Digitale Medien
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  • 8
    ISSN: 1432-0533
    Schlagwort(e): Leucodystrophy Metachromatic ; Electron Microscopy ; Prismatic Deposits ; Brain ; Peripheral Nerve ; Kidney ; Rectum
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Clinical history, light and electron microscopy findings are reported in four cases of infantile metachromatic leucodystrophy. By electron microscopy, the authors describe the various types of lesions and the different lipid deposits noticed in the central and peripheral nervous system, in the kidney and rectum. They stress the prismatic lipid deposits observed not only in the cerebral white matter and in the kidney but in the peripheral nerves as well.
    Materialart: Digitale Medien
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  • 9
    Digitale Medien
    Digitale Medien
    Springer
    Acta neuropathologica 21 (1972), S. 50-60 
    ISSN: 1432-0533
    Schlagwort(e): Hirano Bodies ; Rod-Like Structures ; Inclusions ; Electron Microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary By light microscopy, Hirano bodies are fusiform or spheroidal eosinophilic bodies, that are commonly observed in the hippocampi of the elderly and are especially numerous in patients with various dementias or degenerative diseases. Rarely, they have been demonstrated in other locations and even in animals. Ultrastructurally, the Hirano bodies are complex pleomorphic aggregates of intraneuronal fibrillary material found predominantly in the processes but occasionally in the perikarya. The Hirano bodies are assembled from multiple subunits, but occasionally in the perikarya. The Hirano bodies are assembled from multiple subunits, each consisting of two overlapping or intersecting expanses of parallel filaments. Depending on the plane of section and orientation, the subunit may appear as a lattice-work array of intersecting filaments, a row of regularly spaced punctate densities closely applied to a filament, or a broader feathery fibril. The subunits appear to be derived from the reorganization or precipitation of randomly dispersed finely filamentous material. Because of the diverse circumstance under which they are found, Hirano bodies are regarded as a non-specific manifestation of neuronal degeneration.
    Materialart: Digitale Medien
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  • 10
    Digitale Medien
    Digitale Medien
    Springer
    Acta neuropathologica 21 (1972), S. 89-98 
    ISSN: 1432-0533
    Schlagwort(e): Ionizing Radiation ; Late Effects ; Brain ; Electron Microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The data with which this paper deals were obtained from white rats receiving limited head X-irradiation, tested for behavioral changes, and sacrificed for light and electron microscopic evaluation 1 year after the irradiation. No evidence was found for a general loss or change in cortical or subcortical neurons. On the other hand, there was bilateral focal degeneration in the fimbria of the fornix in the dorsal hippocampus. This involved considerable numbers of pyramidal and granule cells, presumably secondary to delayed vascular changes. Widespread hypertrophy of astrocytes was noted throughout the irradiated zone. Within each central necrotic zone invasive collagen, reticulin and fibrin were present. In general, blood vessels showed only occasional evidence of thickening. However, the blood vessels in the areas of frank necrosis in the fimbria and internal capsule exhibited intense thickening leading to hyalinization.
    Materialart: Digitale Medien
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  • 11
    Digitale Medien
    Digitale Medien
    Springer
    Acta neuropathologica 21 (1972), S. 169-175 
    ISSN: 1432-0533
    Schlagwort(e): Batten's Disease ; Electron Microscopy ; Appendix ; Curvilinear Inclusion
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The electron microscopic findings in the appendix of a five-year-old child suffering from Batten's disease are presented. They revealed accumulations of curviform densities in smooth muscle cells, nerve cells and Schwann cells of the myenteric plexus of Auerbach. Typical lipofuscin pigment was not observed. The presence of transitional forms, however, suggesting progressive transformation of the inclusions into lipofuscin-like granules, is briefly discussed. It is proposed that, during life, electron microscopy of the appendix might be useful for the diagnosis or more specific classification of a form of storage disease.
    Materialart: Digitale Medien
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  • 12
    Digitale Medien
    Digitale Medien
    Springer
    Acta neuropathologica 22 (1972), S. 7-12 
    ISSN: 1432-0533
    Schlagwort(e): Neuroglia ; Identification ; Light Microscopy ; Electron Microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary A simple method is described, using ultrathin sections, by which glial cells of all three types can be identified in the same section without using specialised techniques. Thesame cell can be identified by electronmicroscopy and thus allow for exact correlation of light and electron microscopic features. An outline description of glial types is given.
    Materialart: Digitale Medien
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  • 13
    Digitale Medien
    Digitale Medien
    Springer
    Acta neuropathologica 20 (1972), S. 11-21 
    ISSN: 1432-0533
    Schlagwort(e): Electron Microscopy ; Epilepsy, Experimental ; Focus ; Aluminium Cream ; Neurone
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Cats were given injections of 0.01 cc of alumina cream into the cortex of the medial surface, above the distal part of the sulcus cruciatus. Then for a month the animals were “stimulated” by intravenous injections of penicillin. The electron microscopic study revealed: 1. A proximal zone close to the alumina cream; it is an inflammatory focus characterised by the presence of an exudate in which macrophages, plasmocytes and collagen fibres are present. 2. A middle zone: the astrocytes are hypertrophied and fibrous; the neurons exhibit either neurofibrillary degeneration or considerable increase of the number of mitochondria. Hypertrophied astrocytes and “hyperchondriomated” neurons are envisaged as possible indications of disturbances of electrical activity. 3. A distal zone: in this region the alterations of the cortex disappear.
    Materialart: Digitale Medien
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  • 14
    Digitale Medien
    Digitale Medien
    Springer
    Acta neuropathologica 21 (1972), S. 61-67 
    ISSN: 1432-0533
    Schlagwort(e): Rod-Like Structures ; Ammon's Horn ; Electron Microscopy ; Age Incidence
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary A study of rod-like structures (RLS) was made in 173 pathological and in 67 normal brains. The pathological brains included cases with varied neuropathological conditions: vascular, metabolic, degenerative, infectious, traumatic, neoplastic, etc. The ages of the patients ranged from newborn to 97 years. RLS were found in 152 pathological brains (89%) and in 50 normal brains (75%). RLS were localized in all but one case, in Ammon's horn, specifically in Sommer's sector and in the stratum lacunosum beneath Sommer's sector. There was no correlation between any group of diseases studied and appearance or number of RLS. The number of RLS in Sommer's sector increased with advancing age. In the middle age, ihowever, the stratum lacunosum showed a higher number of RLS. The results of this study idicate that there is no significant relationship between RLS and any pathological condition and therefore that they represent non-specific changes, although a correlation with advancing age is probable. Although RLS appeared to be intracellular, their exact localization was not established.
    Materialart: Digitale Medien
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  • 15
    Digitale Medien
    Digitale Medien
    Springer
    Acta neuropathologica 22 (1972), S. 13-28 
    ISSN: 1432-0533
    Schlagwort(e): Colitoxin Shock ; Blood-Brain Barrier ; Pig ; Electron Microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Ultrastructural alterations of the capillaries and venules in the central nervous system after intravenous application of coli endotoxin were studied in 193–7 weeks-old piglets (conventional, SPF and gnotobiotic). Slight lesions were found in the endothelium of capillaries and venules consisting of focal multiplication of microvilli, pinocytotic vesicles, vacuoles and dense bodies as well as occurrence of leukocytes adhering to the vascular surface being located in the vascular wall. There was severe extravasation in venules and occasionally in capillaries. The intercellular spaces of the neuropil were markedly widened and contained a plasma-like material. An increased number of lysosomes and osmiophilic depots were seen in the neuropil of 4 out of 19 animals resembling the lesions of porcine cerebrospinal angiopathy. Microthrombi, aggregations of platelets and erythrocytes were found in the vascular lumen indicating a disturbance of microcirculation after the application of coli endotoxin.
    Materialart: Digitale Medien
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  • 16
    Digitale Medien
    Digitale Medien
    Springer
    Acta neuropathologica 22 (1972), S. 257-263 
    ISSN: 1432-0533
    Schlagwort(e): Acanthocytosis ; Sural Biopsy ; Electron Microscopy ; Demyelination
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The fine structure of sural nerve biopsies is described in two brothers with normo-lipoproteinaemic acanthocytosis and an associated neurological syndrome. There was a severe reduction of myelinated fibres. The Schwann cells had an increased population of lysosomes and contained remnants of myelin. The myelin lamellae were often split at the intraperiod lines. Centrioles were found in Schwann cells, fibroblasts and endothelial cells. The significance of these findings is discussed.
    Materialart: Digitale Medien
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  • 17
    Digitale Medien
    Digitale Medien
    Springer
    Acta neuropathologica 22 (1972), S. 305-318 
    ISSN: 1432-0533
    Schlagwort(e): Encephalitis, Viral, Experimental ; Electron Microscopy ; Nervous System, Central and Peripheral ; Crystalline Aggregates ; Filamentous Collections
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The CNS and posterior root ganglia of rabbits experimentally infected with Borna virus were studied by electron microscopy. Intracytoplasmic crystalline arrays were common in the non-neuronal cell elements of the central and peripheral nervous tissues of all infected animals. Peculiar filamentous collections were seen occasionally in the central and peripheral neurons of one third of the inoculated rabbits. Control animals showed no such changes. In the affected tissues the nuclear density was increased. There were numerous cells grouped around the vessels or scattered singly or in clusters in the parenchyma. Amongst them plasma cells could be recognized as well as mononuclear cells of hematogenous origin, microglia cells in various reactive stages and macrophages derived from either of the latter cell types. The nonspecific character of the crystalline aggregates is emphasized. The questionable viral nature of the filamentous bundles is considered briefly; other explanations as to their nature are also mentioned. Finally, attention is drawn to the heterogeneous composition of the glial nodules and to the ultrastructural variability of the various cell types found in the inflamed tissues.
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  • 18
    Digitale Medien
    Digitale Medien
    Springer
    Acta neuropathologica 20 (1972), S. 237-247 
    ISSN: 1432-0533
    Schlagwort(e): Neurofilament ; Neuropathy ; Electron Microscopy ; Neurofibrillary Pathology
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Sural nerve biopsy was performed on a six-year-old girl with a slowly progressive distal mixed polyneuropathy. The nerve fiber population was reduced, and of those remaining, approximately half were greatly enlarged, measuring up to 35 microns in cross section. Longitudinal sections showed axonal enlargement to be segmental. Ultrastructurally, swollen axonal segments were filled with neurofilaments in closely-packed swirls which appeared to tie on occasion into granular electron-opaque condensations. Both, myelinated and unmyelinated fibers were involved, and some degree of onion-bulb formation was observed. Although masses of neurofilaments are found in peripheral axons in other disorders, none approaches the proportions encountered in this unique case.
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  • 19
    Digitale Medien
    Digitale Medien
    Springer
    Acta neuropathologica 20 (1972), S. 288-298 
    ISSN: 1432-0533
    Schlagwort(e): Nerve Growth Factor ; Peripheral Nerve Fibres ; Schwann Cells ; Electron Microscopy ; Phase Contrast
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Nerve Growth Factor (NGF) antiserum causes neuronal loss in the sympathetic ganglia of newborn rats. Pre and post ganglionic sympathetic fibers from eleven such animals and eight controls were studied by phase contrast and electron microscopy. Quantitative techniques were applied to the study of different parameters of the axons and Schwann cells. Treated animals showed only 24% of the axonal population of controls and 34% of Schwann cells. This fiber loss was non-selective, affecting all fiber sizes. Schwann cells from treated animals enclosed fewer axons than normal and some contained none. Contrary to what is seen following transection of an unmyelinated nerve, regenerative axonal sprouting was not observed during the 6 week period studied. Schwann cell processes were elongated and unfolded, frequently engulfing bundles of collagen. NGF antiserum experiments provide a tool for the study of axonal and Schwann cell behaviour after neuronal loss avoiding the disadvantages of the traumatic disruption of neural architecture that results from experimental surgical lesions.
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  • 20
    Digitale Medien
    Digitale Medien
    Springer
    Acta neuropathologica 20 (1972), S. 335-347 
    ISSN: 1432-0533
    Schlagwort(e): Spinal Cord Ischemia ; Neurons ; Glycogen ; UDPG-transferase ; Glycogen Phosphorylase ; Histochemistry ; Electron Microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Partial ischemia of the spinal cord in adult cats was induced by abdominal aortic ligation. The most striking abnormality was an accumulation of glycogen in large motor neurons and astroglia in the peripheral anterior horns. Little or no histological and ultrastructural abnormalities were present in these regions. The first glycogen deposits appeared after 1/2 h in glial cells, whereas glycogen accumulation in neurons was first noticeable 1 h after ligation reaching a maximum in 24 h. A gradual decrease occurred with disappearance of glycogen at 10 days. Increase in UDPG-transferase was found preceeding glycogen appearance, and increase in glycogen-phosphorylase activity occurred later concurrent with glycogen accumulation. This unique neuronal glycogen deposition may be due to the UDPG-transferase normally present in γ-motor neurons of the anterior horns. Other possible mechanisms are also considered.
    Materialart: Digitale Medien
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  • 21
    Digitale Medien
    Digitale Medien
    Springer
    Acta neuropathologica 21 (1972), S. 11-22 
    ISSN: 1432-0533
    Schlagwort(e): Microglia ; Cerebral Cortex ; Cold Lesion ; Electron Microscopy ; Phagocytosis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The ultrastructural appearances of microglia in the rat cerebral cortex were examined following experimental cold lesions. It was found that microglia toop up extravascularized plasma by pinocytosis. These pinocytotic vesicles coalesced to form large vacuoles of medium electron density, which subsequently decreased in size and increased in density and morphological complexity. Concurrently the microglial cells underwent dedifferentiation and division. Between 3 and 7 days after making the cold lesion it was difficult to distinguish between phagocytes of microglial and haematogenous origin. The relationship of microglia to haematogenous phagocytes is discussed.
    Materialart: Digitale Medien
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  • 22
    Digitale Medien
    Digitale Medien
    Springer
    Acta neuropathologica 21 (1972), S. 213-223 
    ISSN: 1432-0533
    Schlagwort(e): Hydrocephalus, Experimental ; Cats ; CSF Turnover ; Ependyma ; Subependymal Tissue ; Extracellular Space ; Electron Microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary A light and electron microscopic study of the ependymal and subependymal regions of experimental hdrocephalic cats was made. Hydrocephalus was induced by injection of kaolin into the cisterna magna. Cerebrospinal fluid (CSF) turnover was measured in all experimental cats by ventricular perfusion just prior to glutaraldehyde fixation. The cats were sacrificed at 7 (acute hydrocephalus) and at 21 or more days (chronic hydrocephalus) after kaolin. The major pathological findings were: flattened and outstretched ependymal lining, detachment of ependymal cells and rarefaction of subependymal areas with increase in the extracellular space. The significant morphological alterations in acute hydrocephalus, characterized by a marked decreased rate of CSF absorption, were flattening and outstretching of ependymal cells with minimal rarefaction of subjacent tissues. In the acute animal with a measurable amount of CSF absorption, and more clearly, in the chronic animal with higher rates of CSF absorption, detachment of ependymal calls, significant rarefaction of subependymal tissues, and marked increased subependymal extracellular space were the predominant changes. It is concluded that these pathological changes provide the morphologic substrate for transventricular absorption of CSF.
    Materialart: Digitale Medien
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  • 23
    Digitale Medien
    Digitale Medien
    Springer
    Acta neuropathologica 21 (1972), S. 263-271 
    ISSN: 1432-0533
    Schlagwort(e): Subacute Sclerosing Panencephalitis ; Electron Microscopy ; Nuclear Bodies ; Tubular Inclusions ; Nucleocapsids
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary In this case of documented subacute sclerosing panencephalitis (SSPE), electron microscopy of a brain biopsy revealed a previously unreported “fingerprint” configuration of tubular inclusions or nucleocapsids. The pattern resembled that of the whorled filamentous nuclear bodies which are so frequently encountered in ultrastructural studies of this disease. Furthermore, an apparent tubule was seen running parallel to filaments within the nucleus of still another affected cell. These findings lend support to the concept that nuclear bodies are converted into and/or synthesize nucleocapsids.
    Materialart: Digitale Medien
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  • 24
    Digitale Medien
    Digitale Medien
    Springer
    Acta neuropathologica 21 (1972), S. 282-295 
    ISSN: 1432-0533
    Schlagwort(e): Jimpy Mouse ; Electron Microscopy ; Neuroglia ; Mouse Mutant ; Myelination
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Corpus callosum of Jimpy mouse brain was investigated with the electron microscope in 14, 21, 29 days old animals, and compared with that of normal littermates. Myelination was almost lacking in Jimpy; this absence seems to be due to an agenesis rather than a destruction. The oligodendrocyte cell line is severely disturbed; adult oligodendrocytes are absent in all the animals studied, even in 29 days animals. The few oligodendrocytes present are young; they are found in the vicinity of the few myelinated fibers. Features suggestive of oligodendrocyte death were found both in corpus callosum and neighbouring cortex. The astrocyte cell line develops normally; evidences of cell reactivity such as increase of glycogen and gliofilaments were found. Microglia were present in large numbers and contained several types of inclusions, whose signification is discussed. It is concluded that the defect of myelination in Jimpy mice is closely related to abnormalities found in the oligodendrocyte line.
    Materialart: Digitale Medien
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  • 25
    Digitale Medien
    Digitale Medien
    Springer
    Acta neuropathologica 22 (1972), S. 158-169 
    ISSN: 1432-0533
    Schlagwort(e): Brain Stab Wound ; Glycogen Reaction ; Histochemistry ; Electron Microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Abnormal accumulation of glycogen around cerebral stab wounds was studied histochemically, electron microscopically, and quantitatively in rats 4, 13, 28 days old and in adult (90–150 days old) animals. Glycogen did not accumulate around stab wounds in 4 and in 13-day old rats, whereas a considerable accumulation of glycogen was present in the 28 day and in adult animals. There was a close parallelism between the amount of glycogen accumulated and the degree of maturation of oxidative enzyme activity as reflected by succinic dehydrogenase activity in the cortex. In 28 day and in adult animals, a pale central necrotic core was surrounded by a zone of reduced enzyme activity. The region of glycogen accumulation was located peripherally to this zone.
    Materialart: Digitale Medien
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  • 26
    ISSN: 1432-0533
    Schlagwort(e): Spongy Degeneration ; Cerebellum ; Electron Microscopy ; Enzyme Histochemistry ; Mitochondria
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Electron microscopic and enzyme histochemical studies were performed on the cerebellum from a 9 month old Jewish boy with spongy degeneration. Histologically, the main pathological changes were noted in the Purkinje cell layer, the deeper areas of the granular cell layers and the subcortical white matter. Ultrastructurally, multiple vacuoles were present within the swollen cytoplasm and processes of protoplasmic astrocytes in the cortex, while in the subcortical white matter vacuoles were observed within splitting myelin lamellae as well as within astrocytes. There were also abnormal mitochondria within swollen protoplasmic astrocytic cytoplasm and processes which in ATPase preparations showed little or no reaction product. However, the fibrillary astrocytes were not swollen and contained intact mitochondria which showed normal reaction product in ATPase preparations. Since the myelin changes are known to be nonspecific and secondary to abnormal fluid accumulation, the characteristic distribution of the multiple vacuoles in the central nervous system in this disorder seems primarily to be related to swelling of the protoplasmic astrocytes.
    Materialart: Digitale Medien
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  • 27
    ISSN: 1432-0533
    Schlagwort(e): Lipid Composition ; Axonal Loss ; Ganglioside Deficit ; Schilder's Disease ; Electron Microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary A case of Schilder's diffuse sclerosis with a four-year history of progressive neurologic deterioration in a boy dying at ten years of age is reported. The asymmetry of the process was indicated during life by the clinical findings. A unicentric focus of demyelination was found with the initial stages in the occipital and temporal white matter and a subacute reaction in the rostral cerebral white matter, brain stem, and cerebellum. Electron microscopic study confirmed the extensive axonal loss. No particles compatible with a virus structure were identified. Analysis of the regional composition of cerebral lipids demonstrated large deficits of cerebroside, sulfatide, cholesterol, total phospholipid, sphingomyelin, and ganglioside in the occipital lesion. A significant but less complete deficit of lipids was found at the lesion margin in frontal white matter. An increase of cholesterol esters was demonstrated at this site as well. The normal-appearing white matter of rostral frontal lobe showed a decreased level of ganglioside and normal concentrations of the other structural lipids. This decreased ganglioside concentration of grossly normal white matter suggest the advisability of considering Wallerian degeneration in interpreting the analytical data obtained in the study of the demyelinating disorders. The morphological and biochemical findings indicate the progressive spread of the axonolytic and myelinolytic process in the pathogenesis of Schilder's diffuse sclerosis.
    Materialart: Digitale Medien
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  • 28
    Digitale Medien
    Digitale Medien
    Springer
    Acta neuropathologica 20 (1972), S. 122-138 
    ISSN: 1432-0533
    Schlagwort(e): Mercury Intoxication ; Nerve Cells ; Dorsal Root Ganglion ; Cerebellum ; Electron Microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary When given to rats, both organic and inorganic mercury compounds were found to be neurotoxic. After CH3HgCl intoxication, focal cytoplasmic degradation was the most characteristic lesion observed in the neurons of the dorsal root ganglion. A large cytoplasmic vacuole was formed in many neurons as a result of such lesions. After HgCl2 poisoning, the dorsal root ganglion neurons developed peripheral vacuoles, which were formed by the retraction of the neuron from its surrounding satellite cells. Extensive fragmentation of these neurons occurred as such vacuolation progressed. Multiple small lesions varying from 0.1–1.2 μ were found in the neuronal cytoplasm after both organic and inorganic mercury intoxication. Mercury could be demonstrated histochemically to have a close association with these lesions. In the anterior horn motoneurons, neither mercury compound produced any permanent pathological lesions in the nerve cell bodies, although there was severe dilatation of the cisternae of the endoplasmic reticulum and the nuclear envelope at early stages of the intoxication. In the cerebellum, both organic and inorganic mercury compounds produced extensive coagulative or lucid changes in the granule cells. Degeneration of the Purkinje cells was also found at late stages of the poisoning.
    Materialart: Digitale Medien
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  • 29
    Digitale Medien
    Digitale Medien
    Springer
    Acta neuropathologica 20 (1972), S. 258-263 
    ISSN: 1432-0533
    Schlagwort(e): Electron Microscopy ; Sural Nerve ; von Recklingshausen's Disease ; Schwann Cell ; Onion Bulb
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Examination of photo and electron microscopical preparations of a biopsied sural nerve from a patient with von Recklinghausen's disease is reported. In the toluidine blue stained Epon-sections the number of myelinated fibers per square millimeter was moderately decreased and the number of large myelinated fibers was severely reduced. Large, circular, lamellated structures which resemble the onion bulb were observed. These structures are different from the previously reported onion bulb in their size and core structure which contains usually a degenerated nerve fiber. Some consideration was given to the origin of these onion bulb-like lamellated structures.
    Materialart: Digitale Medien
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  • 30
    Digitale Medien
    Digitale Medien
    Springer
    Acta neuropathologica 22 (1972), S. 333-344 
    ISSN: 1432-0533
    Schlagwort(e): Segmental Demyelination ; Remyelination ; Axon/Schwann Cell Relationship ; Electron Microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Electron microscopic observations were made of early remyelination after segmental demyelination in experimental allergic neuritis (EAN) and experimental diphtheritic neuropathy. In EAN 71% of axons which had been demyelinated were invaginated each within a single Schwann cell; remyelination associated with this cellular relationship was in accordance with the spiral myelin concept, 29% of demyelinated axons in EAN were initially enveloped each by several Schwann cell processes and the associated mechanism of remyelination was by “tunication” resulting in a transient irregular distribution of myelin lamellae around the axon circumference. In diphtheritic neuropathy regeneration more closely paralleled development in ontogeny. 88% of demyelinated axons were invaginated each within one Schwann cell, only 12% of axons were each enveloped by more than one Schwann cell process. Early remyelination by tunication was not observed in diphtheritic neuropathy. Additional loosely associated Schwann cell processes lying within the “old” Schwann cell basement membrane occurred frequently in both experimental conditions. Schmidt-Lanterman clefts, “redundant” myelin, and “desmosomes” were observed in the sheaths of incipient remyelination.
    Materialart: Digitale Medien
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  • 31
    Digitale Medien
    Digitale Medien
    Springer
    Naunyn-Schmiedeberg's archives of pharmacology 275 (1972), S. 299-313 
    ISSN: 1432-1912
    Schlagwort(e): Human Blood Platelets ; Inhibition of Serotonin Uptake ; Lipid Solubility ; Beta-Adrenergic Blocking Agents ; Serotonin Release ; Electron Microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Beta-adrenergic blocking agents inhibit serotonin uptake by human blood platelets; in addition they induce release of the previously accumulated amine in vitro. Propranolol was the most active drug, followed by alprenolol, Kl 255, Kö 592, INPEA, oxprenolol, pindolol, Kö 1366, practolol, and sotalol. Kinetic analysis revealed a mixed type of inhibition of serotonin uptake. A significant correlation between these parameters and the lipid solubilities of the respective drugs was found. In contrast to the active serotonin uptake labelled β-sympatholytics were accumulated by the platelets passively, i. e. independently of temperature and of time of incubation. The degree of accumulation by human blood platelets and human erythrocyte ghosts was again correlated with the hydrophobicity of the compounds. Therefore, it is concluded that these effects of β-adrenergic blocking agents are mainly unspecific in nature, depending on the lipid solubility of the drugs, and leading to conformational changes within the membranes. This assumption is supported by the electron microscopical findings in human platelets, indicating ultrastructural changes and cell lysis.
    Materialart: Digitale Medien
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  • 32
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 127 (1972), S. 270-286 
    ISSN: 1432-0878
    Schlagwort(e): Endocytosis ; Locomotion ; Membrane turnover ; Hyalodiscus simplex ; Morphometry ; Electron Microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung Hyalodiscus simplex zeigt während der normalen Fortbewegung eine auf den Uroidbereich beschränkte permanente Endocytoseaktivität, durch die kontinuierlich Zellmembran und extrazelluläres Milieu ins Innere der Zelle aufgenommen wird. Nach unter-schiedlich langer Inkubation in einer 2.5% igen Thorotrastlösung kann die Markierungssubstanz bei ihrer Passage durch die Zelle morphologisch verfolgt werden. Das endocytierte Thorotrast gelangt in ein intrazelluläres Membransystem, welches für die Verdauung verantwortlich ist und dessen Gesamtoberfläche in der Größenordnung der Zelloberfläche liegt. Verschiedene, funktionell miteinander in Verbindung stehende Vakuolen stellen die charakteristischen Komponenten des intrazellulären Verdauungssystems dar. Die morphometrische Auswertung der Markierungsversuche hat gezeigt, daß der Membran-Turnover etwa 2% pro Minute beträgt. Hyalodiscus simplex benötigt demnach bei normaler Lokomotion zur vollständigen Regeneration der Zellmembran eine Zeit von 7,5–8 Std. Da die Oberfläche trotz permanenter Endocytoseaktivität auch nach unterschiedlich langer Thorotrastinkubation stets konstant bleibt, darf vermutet werden, daß die endocytotisch aufgenommene Zellmembran durch einen noch unbekannten Mechanismus wieder regeneriert wird.
    Notizen: Summary During locomotion Hyalodiscus simplex is active in permanent endocytosis at the uroid region. Thereby plasma membrane and extracellular medium are translocated into the cell interior. After different periods of incubation in a 2.5% solution of thorotrast the tracer can morphologically be followed during the passage through the cell. The ingested thorotrast is collected within a vacuolar system. This system is involved in intracellular digestion and composed of different types of vacuoles, which are structurally separated but functionally interconnected. Its total surface area approximately corresponds to the surface area of the entire cell. As demonstrated by morphometric analysis, the membrane turnover is about 2% per minute. Therefore, in the migrating amoebae 7.5–8 hours are required for the complete regeneration of the plasma membrane. Since the surface area of the cell remains constant despite of permanent endocytotic activity the ingested plasma membrane must be continuously regenerated by an unknown mechanism.
    Materialart: Digitale Medien
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  • 33
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 133 (1972), S. 551-557 
    ISSN: 1432-0878
    Schlagwort(e): Lymphatic capillaries ; Intestinal villus ; Muscularis mucosae ; Guinea pig, Monkey ; Electron Microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung Die zentralen Chylusgefäße in den Zotten des Duodenum und Jejunum von Meerschweinchen und Affe zeigen die Strukturbesonderheiten, die für die Lymphkapillaren des Dünndarms charakteristisch sind. Die Endothelzellen sind durch ihre langen Ausläufer in komplizierter Weise miteinander verzahnt. Sie können an diesen Stellen auseinanderweichen und größeren Chylomikronen den Durchtritt vom extrazellulären Raum in die Lymphkapillaren ermöglichen. Marklose Nervenfasern und vor allem glatte Muskelzellen der Muscularis mucosae treten mit dem Endothel der Lymphkapillaren in Kontakt. Das Zusammenwirken der Endothelverzahnungen mit der Zottenpumpe, die auf den Kontraktionen der glatten Muskelzellen beruht, wird im Hinblick auf den Lymphtransport diskutiert.
    Notizen: Summary The central lacteals in the villi of duodenum and jejunum (Macaca mulatta, Cavia cobaya) exhibit the same structural peculiarities as the lymphatic capillaries in the villi of the small intestine in general. The endothelial cells overlap extensively at their margins. At these points they may be separated from each other so enabling larger chylomicra to pass from the extracellular space into the lumen of the lacteal. Nonmyelinated nerve fibres as well as smooth muscle cells of the Muscularis mucosae in particular contact the endothelium of the lymphatic capillaries. The co-operation of the endothelial interdigitations with the villus pump, realized by the contractions of the smooth muscle cells, is discussed as mechanism of the lymph transport.
    Materialart: Digitale Medien
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  • 34
    ISSN: 1432-0878
    Schlagwort(e): Hypothalamus (Frog) ; Tubero-hypophysial system ; Neurosecretory cell types ; Releasing factors ; Electron Microscopy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Electron microscopic investigation of neural isolated and normal pars ventralis of the tuber cinereum showed the presence, in Rana temporaria, of a tubero-hypophysial neurosecretory system. A striking structural resemblance between this parvicellular, aldehydefuchsin negative, tubero-hypophysial neurosecretory system and the magnocellular, aldehydefuchsin positive, hypothalamo-hypophysial neurosecretory system was observed. Six different neurosecretory cell types are described, characterized by different shape and size of their respective secretory granules. The nature of the secretory product of these cells is briefly discussed.
    Materialart: Digitale Medien
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  • 35
    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.
    Materialart: Digitale Medien
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  • 36
    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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  • 37
    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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  • 38
    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.
    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. 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.
    Materialart: Digitale Medien
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  • 40
    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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  • 41
    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.
    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. 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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  • 43
    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.
    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. 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.
    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. 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.
    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. 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.
    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. 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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  • 48
    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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  • 49
    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.
    Materialart: Digitale Medien
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  • 50
    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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  • 51
    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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  • 52
    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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  • 53
    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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  • 54
    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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  • 55
    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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  • 56
    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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  • 57
    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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  • 58
    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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  • 59
    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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  • 60
    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.
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  • 61
    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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  • 62
    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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  • 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: 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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  • 64
    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.
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  • 65
    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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  • 66
    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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  • 67
    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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  • 68
    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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  • 69
    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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  • 70
    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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  • 71
    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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  • 72
    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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  • 73
    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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  • 74
    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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  • 75
    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.
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  • 76
    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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  • 77
    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.
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  • 78
    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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  • 79
    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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  • 80
    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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  • 81
    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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  • 82
    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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  • 83
    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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  • 84
    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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  • 85
    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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  • 86
    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.
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  • 87
    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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  • 88
    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
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  • 89
    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.
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  • 90
    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.
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  • 91
    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.
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  • 92
    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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  • 93
    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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  • 94
    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
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  • 95
    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.
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  • 96
    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.
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  • 97
    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.
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  • 98
    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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  • 99
    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.
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  • 100
    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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