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  • 1980-1984  (1,490)
  • 1982  (1,490)
  • General Chemistry  (1,159)
  • Atomic, Molecular and Optical Physics  (206)
  • Rat  (125)
  • Nuclear reactions
Material
Years
  • 1980-1984  (1,490)
Year
  • 101
    Electronic Resource
    Electronic Resource
    Springer
    Cell & tissue research 222 (1982), S. 629-634 
    ISSN: 1432-0878
    Keywords: Calcitonin cells ; Anomaly ; Thymus ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In a study of the effect of pinealectomy on thyroid C-cell number, 8 animals out of 66 were found to have thymic tissue in close association with the thyroid. Cells containing immunoreactive calcitonin were found in all of the thyroids but in only one of the 8 pieces of thymus. These cells found in a piece of thymic tissue associated with the right thyroid lobe were located immediately under the capsule and did not form or associate with follicles. Unlike the other animals the rat with thymic calcitonin cells had an unequal distribution of C-cells between the left and right thyroid lobes, but the total number of thyroidal C-cells was the same as that of the other rats. Since the thymus proper was not examined in these 66 animals, ten additional rats were taken for such a study. Thyroid-associated thymic tissue was found in three of these, but none of these thymi showed any immunoreactive cells.
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  • 102
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    Springer
    Cell & tissue research 223 (1982), S. 695-698 
    ISSN: 1432-0878
    Keywords: Pineal gland ; Luteinizing hormone-releasing hormone (LHRH) ; Immunocytochemistry ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Immunoreactive luteinizing hormone-releasing hormone (LHRH)-like material has been demonstrated in the pineal gland of the adult rat. The objective of the present study was to examine the ontogenetic development of this LHRH-like substance in the rat pineal with the peroxidase-antiperoxidase (PAP) method of Sternberger. LHRH-like immunoreactive material was not observed in pineal glands of newborn rats. The amount of material increased progressively from the 6th–12th day of postnatal development. On day 12, the amount of LHRH-like immunoreactivity was consistent and comparable in all pineal glands of male and female animals examined.
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  • 103
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    Springer
    Cell & tissue research 224 (1982), S. 25-31 
    ISSN: 1432-0878
    Keywords: Spleen ; Ig-containing cells ; Immunocytochemistry ; Germinal center ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The morphology and localisation of IgM- and IgG-containing cells in the spleen of rats immunized with sheep red-blood cells (SRBC) were studied by combining immunohistochemical reactions with routine histological and histochemical methods. It was shown that IgM cells occur only in the outer periarteriolar lymphocyte sheath (PALS), whereas IgG cells are present throughout the whole PALS. It has been concluded that these cell types have different routes of migration. Both IgM- and IgG-containing cells were found in the germinal center in close relation with the extracellular immune complexes. The significance of this localisation is discussed.
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  • 104
    Electronic Resource
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    Springer
    Cell & tissue research 224 (1982), S. 195-206 
    ISSN: 1432-0878
    Keywords: Pinealocytes ; Nucleolus ; Rat ; Ultrastructure ; Twenty-four-hour changes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary An ultrastructural and morphometric analysis was made of the nucleolar components in pinealocytes of 40 male Fischer rats sampled at eight times in an LD 12∶12 photoperiod cycle. Comparisons of results from the eight times showed variation in estimated mean volume of the granular component of ±29%, and of the fibrillar component ±11%, in relation to daily means. Peaks in mean volume of total nucleolus and its granular component occurred at 1 h of light. Near maximal and minimal mean volumes of the fibrillar component both occurred during both light and dark. Fibrillar centers (nucleolar organizer regions) of different sizes were found at all sampling times. It is concluded that temporal patterns in 24-h changes in the nucleolar components are most prominent in the granular component, and are more complex than suggested by changes in total nucleolar size or mean dimensions, and than represented by a simple biphasic circadian rhythm. Examples of different stages in the migration of the granular component, and of possible sites of nucleo-cytoplasmic transfer of nucleolar material, are described.
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  • 105
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    Springer
    Cell & tissue research 224 (1982), S. 647-653 
    ISSN: 1432-0878
    Keywords: hCG binding sites ; Endocytosis ; Ovary ; Ultrastructural immunocytochemistry ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Localization of hCG binding sites and the process of endocytosis in pseudopregnant rat ovaries were investigated by indirect electron-microscopic immunocytochemistry. Immature female rats were treated with pregnant-mare serum gonadotropin (PMSG) and human chorionic gonadotropin (hCG) to induce ovarian luteinization. Eight days after priming with PMSG-hCG and 1–6 h before sacrifice the animals were given another injection of hCG to bind the receptors. Receptor sites to hCG localized by reaction product were present in most luteal cells, but not in primary follicular cells. The receptor sites were distributed on luteal cell surfaces facing interstitial spaces. Endocytotic pits containing hCG binding sites were rarely seen 1 h after hCG injection. At 2 h, hCG and presumably its receptor were taken up within endocytotic vesicles with the evidence of reaction product coated on the vesicle wall. With time, fusion of endocytotic vesicles with lysosome occurred and the reaction product appeared in phagolysosomes. The reaction product was localized on phagolysosomal inner surface or in free granular form. These findings suggest that hCG and its receptors were internalized through endocytotic pits and endocytotic vesicles and delivered to lysosomes probably for degradation. An additional experiment for localization of acid phosphatase was also performed to delineate the lysosomes and phagolysosomes.
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  • 106
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    Cell & tissue research 225 (1982), S. 229-234 
    ISSN: 1432-0878
    Keywords: Preovulatory follicle ; Cell division ; Age ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The pattern of follicular development during the estrous cycles of aged rats was examined and compared with that of mature rats. In both, preovulatory follicles are derived from a select group of small pre-Graafian follicles which begin to develop at estrus and reach the preovulatory size by the morning of proestrus, but the rate of growth, as judged by an increase in the percentage of granulosa cells incorporating 3H-thymidine, is accelerated in the follicles of aged rats. A second mechanism, which accounts for preovulatory follicles in aged rats, involves the rescue from atresia of pre-Graafian and preovulatory follicles. The existence of this mechanism is supported by the observation that at metestrus in aged rats virtually all follicles, regardless of their state of atresia, possess a high percentage of granulosa cells incorporating 3H-thymidine, indicating that the follicles are growing rapidly. However, some of these rapidly growing follicles show signs of atresia such as pyknotic nuclei within their granulosa cell layers. Since follicles in the initial stage of atresia contain defective oocytes (Peluso et al. 1979b), their rescue and development into preovulatory follicles would result in the ovulation of defective oocytes, a fact which accounts in part of the lower fertility in these older animals.
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  • 107
    ISSN: 1432-0878
    Keywords: Rat ; Cold adaptation ; Skeletal muscle ; Mitochondria ; Fat ; Morphometry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Growing rats (4 weeks old) were kept for 3 weeks at 11° C and 24° C respectively. The cold-adapted animals showed a significantly higher oxygen consumption (64%). Volume density of subsarcolemmal and interfibrillar mitochondria as well as volume density of fat droplets were estimated in M. soleus and the diaphragm of both groups. In cold-adapted animals, the total volume of mitochondria was significantly increased by 24% in diaphragm and 37% in M. soleus. The volume of subsarcolemmal mitochondria was almost doubled in each muscle, but the volume of interfibrillar mitochondria did not change significantly. The surface of the inner mitochondrial membranes per unit volume of mitochondrion in M. soleus was significantly increased both in interfibrillar and subsarcolemmal mitochondria, whereas the surface of the outer mitochondrial membranes per unit volume of mitochondrion was increased only in the subsarcolemmal mitochondria. The volume of fat droplets in the diaphragm and M. soleus of cold adapted animals increased significantly by 62% and 150% respectively.
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  • 108
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    Cell & tissue research 225 (1982), S. 469-485 
    ISSN: 1432-0878
    Keywords: Microglial cells ; Postnatal development ; Enzyme histochemistry ; NDPase, TPPase ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The postnatal development of microglial cells was investigated in the neonatal rat brain by use of light- and electron microscopy, including enzyme-histochemical techniques. Microglial cells were selectively stained by demonstration of their nucleoside diphosphatase (NDPase) activity and classified into three types: 1) In the early postnatal period, “primitive microglial cells” showing scantily ramified processes were found in the cerebral cortex, the hippocampal formation, and the hypothalamus. During the course of the first postnatal week the processes of this cell type developed gradually and the cells were transformed into typical ramified microglial cells, called “resting microglial cells”. 2) “Amoeboid microglial cells” showing typical features of macrophages were characteristic of the cerebral white matter. 3) “Round microglial cells” possessing a round soma and few pseudopodia but no characteristic processes occurred in large numbers in the sub ventricular zone of the lateral ventricle and as single elements in the vicinity of blood vessels. Histochemically, thiamine pyrophosphatase (TPPase) was demonstrated only in the fully developed, ramified microglial cells (“resting microglial cells”), which could be readily observed in the central nervous tissue from the age of 14 day. “Round and amoeboid microglial cells” did not show TPPase activity and disappeared after 14 days of postnatal life. By use of electron microscopy, in neonatal rats NDPase activity was apparent in the plasma membrane of the three types of microglial cells (“primitive, round, and amoeboid” types). They showed basically similar submicroscopic characteristics, i.e., well-developed Golgi apparatus, long strands of roughsurfaced endoplasmic reticulum, single dense bodies and vacuoles, and numerous ribosomes. “Amoeboid microglial cells” were characterized by their well-developed cytoplasmic vacuoles and phagocytic inclusion bodies. The present study strongly suggests a mesodermal origin for these microglial elements.
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  • 109
    ISSN: 1432-0878
    Keywords: Luteinizing hormone ; releasing hormone ; Immunocytochemistry ; Distribution ; Forebrain ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The distribution of luteinizing hormone-releasing hormone (LHRH)-immunoreactive perikarya and processes was examined, in the untreated rat, with the unlabeled antibody enzyme method of immunocytochemistry on thick 50 μm vibratome sections. LHRH neurons were primarily observed in the preoptico-anterior hypothalamic and septal areas. Projections from these cell bodies to the median eminence form three distinct pathways, one laterally along the course of the optic tracts, one medially through the periventricular stratum of the third ventricle, and one through the tractus infundibularis. In addition, some of these cell bodies project to the organum vasculosum of the lamina terminalis (OVLT) and the subfornical organ (SFO). LHRH immunoreactive neurons were also noted in the anterior olfactory regions; they project along the medial olfactory tract to the olfactory bulb.
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  • 110
    ISSN: 1432-0878
    Keywords: Cholecystokinin ; Spinal cord ; Immunocytochemistry ; Rat ; Neuropeptides
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Cholecystokinin-like immunoreactivity has been demonstrated by radioimmunoassay and immunocytochemistry in the spinal cord of various mammals, in particular in nerve fibers of the superficial layers of the posterior column, but had not been detected in neuronal cell bodies. We report immunohistochemical evidence for the presence of a group of cholecystokinincontaining neuronal cell bodies in the lumbar spinal cord of the rat. This group of cells is only visualized after direct injection of colchicine into the spinal cord and is located near the central canal in the intermedio-medial nucleus of area X of Rexed.
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  • 111
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    Cell & tissue research 223 (1982), S. 493-506 
    ISSN: 1432-0878
    Keywords: Microglial cells ; TPPase ; NDPase ; Synapse ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Electron-microscopic survey of selectively stained microglial cells in the cerebral cortex of the rat reveals that the processes of this cell type often encircle axo-dendritic synapses. Enzyme-histochemical methods for thiamine pyrophosphatase (TPPase) or nucleoside diphosphatase (NDPase) were used for the selective marking of the microglial cells; TPPase and NDPase activities were observed in the plasma membrane of microglial cells. The synapses encircled by microglial processes displayed presynaptic structures containing round clear vesicles (50 nm in diameter) and a prominent thickening of the postsynaptic membrane. In vitro, the above-mentioned enzymatic activities were completely suppressed by neuroactive agents such as catecholamines and phenothiazine derivatives. Examination using enzyme-histochemical techniques suggests that a single enzyme may be responsible for both above-mentioned enzymatic reactions. The functional significance of microglial cells in the normal central nervous tissue is discussed.
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  • 112
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    Cell & tissue research 224 (1982), S. 247-267 
    ISSN: 1432-0878
    Keywords: Serotonin ; Brainstem ; Immunohistochemistry ; Rat ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The morphological characteristics and distribution of the somata of serotonin-containing neurons in the brainstem of rats and cats were studied by use of the peroxidase-anti peroxidase (PAP) immunohistochemical method employing highly specific antibodies to serotonin. Antibodies were raised in rabbits against an antigen prepared by coupling serotonin to bovine thyroglobulin and using formaldehyde as the coupling reagent. The distribution pattern of serotonin neurons observed in the present material is essentially in agreement with that described by other investigators who used the Falck-Hillarp method. In addition, this immunohistochemical technique revealed serotonin-containing perikarya in the following regions: 1) the periaqueductal gray, especially lateral to the nucleus raphe dorsalis, 2) the nucleus interpeduncularis, 3) the nucleus parabrachialis ventralis and dorsalis, 4) the field of the lemniscus lateralis, and 5) the reticular formation of the pons and medulla oblongata. The described immunohistochemical procedure makes it possible to study central serotonin neurons in detail without pharmacological pretreatment. The wide distribution of serotonin neurons demonstrated in this study should be considered when interpreting experiments dealing with the serotonin system.
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  • 113
    ISSN: 1432-0878
    Keywords: ACTH/β-endorphin neurons ; Synapse ; Hypothalamus ; Immunohistochemistry ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In the preinfundibular portion of male rat hypothalamus, the arcuate-median eminence region was examined after staining with anti-porcine ACTH 1-39 serum. In several cases, anti-β-endorphin serum was also employed. Both sera stain the same cell bodies. The cell bodies of the immunoreactive neurons are scattered in the subependymal layer, arcuate nucleus and lateral tuberal region. Fibers originating from these cell bodies are distributed extensively throughout these regions. They make synaptic contacts on immunonegative fibers in the arcuate nuclei, or terminate directly in the perivascular space in the internal layer of the median eminence. The fibers, however, are very scarce in the external layer of the median eminence, and do not directly terminate on the neurovascular contact surface. These findings suggest that the ACTH/β-endorphin neuronal system may serve neuronally and humorally as an intrahypothalamic constituent of the hypothalamic pituitary regulation system.
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  • 114
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    Cell & tissue research 224 (1982), S. 455-458 
    ISSN: 1432-0878
    Keywords: Intravagal paraganglia ; Paraganglion supracardiale vagi ; Recurrent nerve ; Vagus nerve ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In the Ham-Wistar rat, a paraganglion was found within the vagus nerve at the site of branching of the recurrent laryngeal nerve. Due to its location the name “paraganglion supracardiale vagi” is suggested. Fluorescence microscopy of the paraganglionic cells displays an intense yellow-green fluorescence indicating the presence of biogenic amines. Ultrastructurally, chief cells containing dense-core vesicles form three kinds of synaptic contacts (afferent, efferent and reciprocal) with enlarged, mitochondria-rich nerve endings.
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  • 115
    ISSN: 1432-0878
    Keywords: Monoadrenalectomy ; Compensatory adrenal growth ; Zona fasciculata ; Rat ; Stereology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructural changes associated with the compensatory hypertrophy of the zona fasciculata cells on monoadrenalectomized rats were investigated by stereological techniques. It was found that these subcellular changes display a different pattern from those underlying the ACTH-induced adrenocortical cell growth in the intact rats. This result supports the view that compensatory adrenal hypertrophy does not involve activation of the hypothalamo-hypophyseal-adrenal axis.
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  • 116
    ISSN: 1432-0878
    Keywords: Pudendal nerve ; Sensory neurones ; Spinal ganglion ; Transganglionic labelling (HRP) ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The morphology and distribution of the sensory neurones of the pudendal nerve within the spinal ganglia of rats were investigated by use of horseradish peroxidase (HRP). The labelling was visualized in diaminobenzidine (DAB) or tetramethyl-benzidine (TMB)-stained sections. Injection of HRP directly into the pudendal nerve labelled perikarya predominantly in the sixth lumbar DRG (L6). Following injection of HRP into the scrotal skin, however, additional cells were labelled in L5 and SI. Labelling was invariably unilateral. Approximately equal numbers of small (〈30 μm) and large neurones (〉40 μm) were labelled following subcutaneous injections although injections into the nerve marked twice as many small cells as large cells. This suggests that, in the rat, most of the small-diameter fibres within the pudendal nerve ascend through L6. Although a cluster of neurones was observed in one experiment, the remaining 25 experiments did not reveal any somatotopic arrangement since the labelled perikarya were distributed evenly throughout the ganglion. Similar numbers of retrogradely labelled neurones (somatopetal transport of the tracer) were observed in both DAB- and TMB-stained sections, although TMB allowed the demonstration of anterograde (somatofugal) HRP transport by terminal labelling in the superficial laminae of the lumbar spinal cord, extending into laminae II–IV.
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  • 117
    ISSN: 1432-0878
    Keywords: Carotid body ; Glomus cells ; Endocytosis ; Cationized ferritin ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Glomus cells from carotid bodies of adult rats dissociated by means of collagenase or collagenase + trypsin were used to study by electron microscopy the endocytotic uptake of cationized ferritin (CF) tracer into subcellular compartments. The glomus cells were incubated with the tracer (1) in a basic salt medium (BM), or (2) in the BM into which calcium ionophore A23187 had been added, or (3) in a potassium-rich medium. Incubation of the cells in BM containing CF for 30 min resulted in attachment of the tracer to the cell membrane and uptake of a few solitary tracer particles into small vesicles and multivesicular bodies. No uptake into the cisternae of the Golgi apparatus was observed. Further incubation in BM containing CF for another 30 min resulted in increased uptake of the tracer into small vesicles and multivesicular bodies. A similar pattern of uptake was observed when the dissociated glomus cells were first preincubated in BM with CF for 30 min and then incubated for 1 min or 30 min in the BM solution containing both the ionophore and CF. Upon such incubation, CF particles were seen to penetrate into coated pits and sites of exocytosis at the cell surface. When the 30-min preincubation in BM was followed by incubation in a CF-containing potassium-rich medium for 15–30 min, uptake into vesicles, small lysosomes and occasionally also into profiles of the smooth endoplasmic reticulum was seen. Endocytotic mechanisms of the glomus cells are outlined.
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  • 118
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    Cell & tissue research 227 (1982), S. 93-112 
    ISSN: 1432-0878
    Keywords: Neurophysins ; Immunocytochemistry ; Age-dependent changes ; Hypophysectomy ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The hypothalamo-extrahypophyseal neurophysin pathways (HEH) and the three hypothalamic nuclei secreting neurophysins, the supraoptic (SON), paraventricular (PVN) and suprachiasmatic (SCN) nuclei, of normal and hypophysectomized rats were studied by application of the immunoperoxidase procedure. Eight well-defined HEH pathways were recognized. Their main sites of projection were: lateral septum and subfornical organ (1 and 2); tractus diagonalis (3); medial nucleus of the amygdala and lateral ventricle (4); nucleus periventricularis thalami, nucleus habenulae lateralis and periaqueductal gray (5); periaqueductal gray, pineal organ, collicular recess and subependymal region of the fourth ventricle (6); dorsomedial nucleus and premammillary area (7); perimammillary region, corpus trapezoideum, ventral surface of medulla oblongata, nucleus tractus solitarii, nucleus commissuralis, substantia gelatinosa and formatio reticularis lateralis of the medulla oblongata and spinal cord (8). Neurophysin fibers of unknown origin were found in the frontal cerebral cortex. It was noted that in pathway 5 the amount of immunostainable material undergoes changes with age. The three neurophysin-secreting nuclei reacted differently following hypophysectomy. Among the HEH pathways the only one that seemed to be affected by hypophysectomy was that innervating the lateral septum. It is suggested that the neurons that survive hypophysectomy either do not project to the neural lobe or, alternatively, display axon collaterals projecting outside the neural lobe. Such a neuronal population could be the origin of the HEH pathways.
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  • 119
    ISSN: 1435-2451
    Keywords: Rat ; Organ transplantation ; Technique ; Ratte ; Organtransplantation ; Technik
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Über 3000 Transplantationen wurden unter Verwendung der renalen Gefäße für Herz, Nieren, Leber und Pankreastransplantationen durchgeführt: Empfänger Herz Niere Leber Pankreas a. coeliaca carotis comm. a. renalis a. coeliaca a. coeliaca v. renalisa. pulmonalis v. renalis vena cava vena portae ureter - ureter duct chol. duct chol. Die Verwendung der renalen Gefäße erwies sich als geeignete Methode mit niedriger Empfängermortalität, sie ermöglicht „End zu End”-Anastomosen, die sicherer sind als „End-zu-Seit”.
    Notes: Summary More than 3000 transplants were performed using the renal vessel for heart, kidney, liver, and pancreas: Recipient Heart Kidney Liver Pancreas Renal artery Common carotis Renal artery Coeliac artery Coeliac artery Renal vein Pulmonal artery Renal vein I.V.C. Portal vein Ureter - Ureter Bile duct Bile duct The use of the renal vessels provides a convenient and accessible site with low recipient mortality for simple end-to-end anastomoses, which are safer then end to side.
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  • 120
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    Langenbeck's archives of surgery 356 (1982), S. 159-166 
    ISSN: 1435-2451
    Keywords: Bile acid ; Reflux ; Stomach surgery ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Am standardisierten Tiermodell an der Ratte wurde die Höhe des duodenogastrischen Refluxes acht Monate nach SPV mit und ohne Pyloroplastik untersucht. Zur Bestimmung des Refluxes diente die enzymatische Messung der Gallensäurenkonzentration im intraoperativ entnommenen Mageninhalt. Als Vergleichsgruppen dienten Laparotomie, alleinige Pyloroplastik und als obligates Refluxmodell die Resektion nach BII ohne Enteroanastomose. Die Höhe des duodenogastrischen Refluxes war nach SPV mit und ohne Pyloroplastik signifikant niedriger als in der Kontrollgruppe. Tiere mit alleiniger Pyloroplastik zeigten einen signifikant erhöhten Reflux. Die BIIGruppe hatte einen fünffach höheren Wert als die Kontrollgruppe. Aufgrund der Pyloroplastik als Drainageoperation kommt es am Rattenmagen nach SPV nicht zur Retention von Speiseresten, die man nach SPV ohne Pyloroplastik beobachtet. Aber wegen der verzögerten Magenmotilität legt sich eingedickter Speisebrei vor den Magenausgang und reduziert so den duodenogastrischen Reflux. Nach unseren Ergebnissen kann ein vermehrter duodenogastrischer Reflux nach SPV mit und ohne Pyloroplastik keine morphologischen Veränderungen der Magenmucosa verursachen.
    Notes: Summary Using rats in a standardized animal experiment, the extent of duodenogastric reflux was studied eight months postoperatively following SPV with and without pyloroplasty. The reflux was determined by enzymatically testing the concentration of bile acid secretion withdrawn from the stomach intraoperatively. Serving as comparison were laparotomies, simple pyloroplasties, and the obligatory reflux models: resection after Bll without enteroanastomosis. After SPV with and without pyloroplasty, the extent of duodenogastric reflux was less than in the control group. Specimens with simple pyloroplasty displayed a significantly greater reflux. The Bll group had a fivefold higher reflux than the control group. Since pyloroplasty can be considered a drainage operation, there is no retention of food particles in the stomach of the rat following SPV - an occurrence expected after SPV without pyloroplasty. However, due to the retarded stomach motility, the thickened chyme tends to linger at the opening of the stomach, thus reducing the duodenogastric reflux. According to our investigations, an increased duodenogastric reflux following SPV with or without pyloroplasty does not induce changes in the mucosa of the stomach.
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  • 121
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    Langenbeck's archives of surgery 357 (1982), S. 105-116 
    ISSN: 1435-2451
    Keywords: Vagotomy ; Gastric cancer ; Bacteria ; Nitrite ; N-Nitroso compounds ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Der Einfluß einer trunculären Vagotomie in Kombination mit verschiedenen Drainageoperationen (Pyloroplastik, Gastroenterostomie ohne Enteroanastomose, Y-Roux-Gastroenterostomie) wurde im Hinblick auf eine Carcinomgefährdung des vagotomierten Magens tierexperimentell an männlichen Wistarratten untersucht. Es wurde überprüft, inwieweit hiernach im Vergleich zu einer nicht-vagotomierten Kontrollgruppe Schleimhautveränderungen auftreten, die unter Exposition mit dem Carcinogen MNNG zeitlich früher und häufiger zur Carcinomentstehung prädisponieren. Als mögliche wichtige cocarcinogene Faktoren wurden zusätzlich die intragastrale Bakterienflora und Nitrit-Konzentration der einzelnen Versuchsgruppen untereinander verglichen. Es zeigte sich, daß der Schweregrad gefundener Magenschleimhautveränderungen, sowie das Ausmaß der bakteriellen Besiedlung und die Nitrit-Konzentration im Magensaft neben der durch Vagotomie angestrebten Säurereduktion vor allem durch Störung der Magenmotilität oder einen enterogastrischen Reflux verstärkt wird. Die Ergebnisse der Untersuchungen sprechen dafür, daß nach Vagotomie, soweit eine ausreichende Magenentleerung gesichert und diese nicht durch einen enterogastrischen Reflux (Gastroenterostomie) erkauft wird, das Risiko für ein Operationsfolgecarcinom gering anzusehen ist.
    Notes: Summary To assess the possible risk of cancer in the operated stomach, the influence of truncal vagotomy combined with different operative drainage procedures (pyloroplasty, gastro-enterostomy without entero-anastomosis, Roux-en-Y gastro-enterostomy) was studied in animal experiments. The aim of the study was to determine whether, compared to controls an earlier and higher incidence of precancerous epithelial lesions or cancers in the stomach occurs in vagotomized animals after oral administration of carcinogens (MNNG). To consider conditions, that may predispose to in vivo formation of carcinogenicN-nitroso compounds, bacterial flora and intragastric nitrite concentration were measured and compared in the various operative groups. The severity of induced epithelial lesions and the quantity of bacterial growth and nitrite concentration in the gastric juice were influenced, apart from the reduction of acid output after vagotomy, mainly by prolonged gastric stasis or the degree of enterogastric reflux. The results suggest that there is probably no increased risk of cancer following vagotomy, if sufficient gastric clearance is guaranted and enterogastric reflux is largely excluded.
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  • 122
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    Cell & tissue research 222 (1982), S. 691-693 
    ISSN: 1432-0878
    Keywords: Jugular vein ; Histochemistry ; Adrenergic innervation ; Cholinergic innervation ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The autonomic innervation of rat jugular vein was studied using glyoxylic acid fluorescence and acetylcholinesterase histochemical methods. The rat jugular vein is provided with both adrenergic and cholinergic nerve fibers organized in plexuses located at the adventitial-medial border. The existence of these nerve plexuses does not seem to support biochemical findings that suggest a lack of innervation in the rat jugular vein and which propose this blood vessel as a model for the analysis of drug-smooth muscle cell interaction without the interference of neuronal uptake mechanisms.
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  • 123
    ISSN: 1432-0878
    Keywords: Uterus ; Epithelial cells ; Tight junctions ; Pregnancy ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructure of tight junctions between uterine luminal epithelial cells of the pregnant rat was studied by the freeze-fracture technique. On day 5 of pregnancy, the day of implantation, the region of tight junctions extended three times as far down the lateral cell membrane as on day 1 of pregnancy, and the strands of the complex interlinked more frequently. These observations suggest that tight junctions on day 5 may be more efficient in preserving the contents of the uterine lumen from dilution or escape than at earlier times of pregnancy.
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  • 124
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    Cell & tissue research 223 (1982), S. 603-614 
    ISSN: 1432-0878
    Keywords: Kidney ; Medullary collecting duct ; Rat ; Rabbit ; Tight junctions ; Freeze ; fracture electron microscopy ; Urinary concentration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The tight junctions along the medullary collecting duct in the kidneys of the rat and the rabbit were studied with freeze-fracture electron microscopy and quantitated according to the number of strands and the apico-basal depth (nm) of the junctions. The most elaborate tight junctions were found in the inner stripe of the outer medulla; rat: 10.6±0.8 strands and 205±24nm; rabbit: 11.6±2.4 strands and 291±55 nm. The elaboration of the tight junctions decreased continuously towards the papillary tip. Inner zone I; rat: 9.3±2.6 strands and 186±38nm, rabbit: 9.5±2.3 strands and 247±59nm. Inner zone II; rat: 7.1±2.2 strands and 129±32nm, rabbit: 8.5±1.4 strands and 199±26nm. Inner zone III; rat: 6.0±1.6 strands and 111 + 19 nm, rabbit: 7.0±1.5 strands and 183±43 nm. In the inner zone III comprising the papillary tip tight junctions with only 1–3 strands were not infrequently seen. Preliminary findings in the kidney of the golden hamster indicate a similar decline of junctional tightness along the collecting duct. These morphological observations suggest that the permeability of the paracellular pathway of the medullary collecting duct increases towards the tip of the papilla, especially in the rat. The functional implications for the medullary recycling of urea and electrolytes, and for the urinary concentrating mechanism are discussed. In addition, the tight junctions of the papillary epithelium are described.
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  • 125
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    Cell & tissue research 226 (1982), S. 1-12 
    ISSN: 1432-0878
    Keywords: Serotonin-immunoreactive nerve fibers ; Cerebellum ; Cat ; Rat ; Immunohistochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The localization of serotonin (5-HT)-immunoreactive nerve fibers in the cerebellum of the rat and cat was investigated by means of the peroxidase-anti-peroxidase (PAP) method using highly specific antibodies to 5-HT. Serotonin-containing nerve fibers were distributed throughout the entire cerebellum including the deep cerebellar nuclei, while 5-HT-positive neuronal somata were not detected in the cerebellum of either species. A different pattern of 5-HT innervation was found among the three layers of the cerebellar cortex. There were also interspecific differences in the pattern of distribution of 5-HT. In the rat, the pool of 5-HT nerve fibers mainly consisted of tangential elements, which were predominant in the molecular layer, while in the cat only a few 5-HT fibers were found in the molecular layer of the cerebellar cortex; dense networks of 5-HT nerve fibers were present in the granular layer. Some differences are evident in the pattern of distribution of 5-HT fibers in cerebellar regions classified on an anatomical and functional basis.
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  • 126
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    International Journal of Quantum Chemistry 21 (1982), S. 147-151 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: We estimate radii of convergence of the Rayleigh-Schrödinger perturbation expansions for various energy levels of the π-electron model of the benzene molecule, described by the Hubbard Hamiltonian in both weakly and strongly correlated limits. They are determined using a “generalized” Cauchy criterion applied to the numerically determined coefficients of the pertinent expansions.
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  • 127
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    International Journal of Quantum Chemistry 21 (1982), S. 1-2 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 128
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    International Journal of Quantum Chemistry 21 (1982), S. 27-68 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The paper is introduced by a description of the role of divergent series in mathematics and their particular use in quantum mechanics. It is emphasized that there is a formal similarity between divergent series in nonrelativistic quantum mechanics and those series occurring in quantum field theory. It is indicated that studies of divergent series in nonrelativistic quantum mechanics can be helpful in the verification of suminability techniques in quantum field theory. The general problems of the application of perturbation theory to the study of the hydrogen atom in external fields are discussed. It is shown how the problem of the continuous spectrum can be bypassed. Further it is shown that algebraic techniques are very useful for a transparent formulation of perturbation theory. The theory is applied to the study of the hydrogen atom in a magnetic field and in an electric field and also to the study of the hydrogen molecule ion. The results for the hydrogen atom in a magnetic field and the hydrogen molecule ion are discussed in detail and the large order behavior of perturbation terms is compared with analytic formulas. Finally the questions of the summability for the series corresponding to the quartic anharmonic oscillator and the hydrogen atom in a magnetic field are discussed. It is seen that large order perturbation theory can be built into a continued fraction representation of a divergent perturbation series. Numerical results are presented for the two perturbation series mentioned above.
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  • 129
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    International Journal of Quantum Chemistry 21 (1982), S. 133-146 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The problem of direct Padé summation of Rayleigh-Schrödinger perturbation coefficients for the H atom Stark effect is discussed in light of the location of the Padé representation of the expected Bender-Wu branch cuts in the complex F (field) plane. The resulting conclusion that such direct summation of the divergent perturbation expansion [for the real part of E(F)] might give suggestive, but certainly not convergent, results is documented. The relationship between the Padé problem of representation of cuts and corresponding problems in L2-discretized scattering theory is pointed out. An alternative Padé expansion with newly placed cuts is proposed which is expected to, and indeed does, have excellent convergence properties for real F. The real and imaginary parts of the Stark broadened and shifted hydrogenic ground state are thus obtained directly from the (real) Rayleigh-Schrödinger perturbation coefficients for a large range of fields indicating the power and simplicity of the method.
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  • 130
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    International Journal of Quantum Chemistry 21 (1982), S. 179-190 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: We present summary results of a bound-state perturbation theory for a one-space and one-time dimension nonrelativistic spinless (Schrödinger) particle, a relativistic spinless (Klein-Gordon) particle, and a relativistic spin-half (Dirac) particle in central fields due to scalar or fourth-component vector-type interactions for an arbitrary bound state. This is accomplished by the reduction of the wave equations to Ricatti form. This enables a decoupling between the pair of coupled first order differential equations on the large and small component Dirac wave functions or a decoupling of the second order differential equation in the Schrödinger or Klein-Gordon equations. All corrections to the energies and wave functions, including corrections to the positions of the nodes in excited states, are expressed in quadratures in a hierarchial scheme, without the use of either the Green's function or the sum over intermediate states. For the ground states of a Schrödinger particle, it is possible to extend this technique to multidimension in the case where the perturbation is due to noncentral fields, for example, in the problem of a nonrelativistic hydrogen atom in a linear combination of multiple fields.
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    International Journal of Quantum Chemistry 21 (1982), S. 209-211 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 132
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    International Journal of Quantum Chemistry 21 (1982), S. 239-250 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A molecular theory of phase transitions in fatty acid monolayers at the air/water interface is proposed based on rotational ordering of molecules about their longitudinal axes. The first order statistical mechanical lattice model of Bell, Mingins, and Taylor (BMT) which is an equilibrium diluted Ising model is used to describe the monolayer behavior of some simple aliphatic carboxylic acids. The interaction energy parameters in the BMT model are adjusted to give reasonable agreement with the experimentally observed chain length dependence, and the energies thus obtained are compared with those calculated for interacting aliphatic carboxylic acid dimers by the technique of perturbative configuration interaction using localized orbitals (PCILO). It is concluded that intermolecular rotational ordering due to the anisotropy of the intermolecular potential plays a significant role in simple fatty acid monolayer phase behavior. A possible experimental test of the model is briefly described.
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  • 133
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    International Journal of Quantum Chemistry 21 (1982) 
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    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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    International Journal of Quantum Chemistry 21 (1982), S. 369-398 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The superoperator formalism for matrix propagators is reviewed, with special attention to the validity of superoperator resolution of the identity. The equation of motion for the particle-hole propagator is discussed. Decoupling procedures based on inner projections and partitioning are examined showing the desirability of self-consistent approximations. The conditions under which a state can be a vacuum for a given linear manifold of operators are analyzed.
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    International Journal of Quantum Chemistry 21 (1982), S. 475-485 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The total (elastic and inelastic) intensity of electrons scattered by CO2 was measured in the s range of 1 to 12 Å-1 and compared with the theoretical intensity calculated from the Hartree-Fock molecular wave function and those calculated for the independent-atom-model (IAM) molecule. In the range of s ≲ 4 Å-1 the electron correlation effect on the total scattered intensity was found to be represented by that for the IAM molecule.
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    International Journal of Quantum Chemistry 21 (1982), S. 557-563 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The electronic structures of TTF, TTF1+, and TTF2+ are described by means of an ab initio Hartree-Fock-Slater procedure with a double-zeta STO basis. Electronic and photoemission spectra, bonding, and charge distributions are discussed and compared to experiments and previous calculations.
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  • 137
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    International Journal of Quantum Chemistry 21 (1982), S. 885-897 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The reduced local energy EL of Rothstein and co-workers is discussed as a criterion for the local accuracy of approximate wave functions. The behavior of EL for different approximation levels is discussed. It is shown that, for particular classes of wave functions, fluctuations of EL reflect local inaccuracies of the wave function as compared to certain convergence limits. The applicability of this criterion is illustrated with approximate Hartree-Fock wave functions for water and methane.
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    International Journal of Quantum Chemistry 21 (1982), S. 927-935 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Starting from the Hohenberg-Kohn functional we show that when the energy density is given as a function of ρ and ∇ρ, i.e., ξ = ξ(ρ, ∇ρ), the condition ∇ρ · n = 0 (which was found by Bader et al. to define virial fragments), appears as a natural boundary condition for the variation of this functional. We also show that when the energy density includes second order derivatives (∇2ρ) this condition is necessary but not sufficient to guarantee the vanishing of the variation. The implications of these results are discussed in the context of a density functional theory for virial fragments.
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  • 139
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    International Journal of Quantum Chemistry 21 (1982) 
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    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 140
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    International Journal of Quantum Chemistry 21 (1982), S. 967-991 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A method for calculating ab initio electronic excitation energies of molecular crystals, based on a many-electron tight-binding approximation, is described. The method follows Frenkel's model for excitons and allows a many-electron treatment of the band-structure problem of molecular crystals. The case of hole bands is studied in detail and various versions of the method are considered. A computational scheme is proposed, in which approximate correlation corrections to the HFR matrix equations of the one-electron LCMO method are calculated. The main effects contributing to these corrections are the effect of relaxation of a molecular ion, the effect of intramolecular electronic-correlation change, and the effect of polarization of the remaining molecules in a crystal. The method developed in the present paper is applied to calculation of the hole bands of the HCP helium crystal.
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  • 141
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    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: An ab initio method for calculating the energies of excess-electron bands in a molecular crystal is developed. These energies represent the electron affinities of a crystal. The present method employs a tight-binding approximation to describe the molecules in a crystal and a set of local functions to describe the excess electron. One- and many-electron formulations of the method are given, the latter takes into account the effect of polarization of all the molecules in the crystal by the excess electron. A scheme for approximate determination of the electronic-correlation corrections to the one-electron bands is developed and applied to calculation of the excess-electron bands in the HCP helium crystal.
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    International Journal of Quantum Chemistry 21 (1982), S. 1041-1050 
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    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The theory by which a wave function may be factorized into conditional and marginal amplitudes is extended to the domain of approximate wave functions. The approximate conditional and marginal factors are well defined, and the marginal factor satisfies a variation principle that is equivalent to a reduced Schrödinger equation having the same form as that derived in the case of exact wave functions. Of the two ways of calculating the effective potential in the reduced Schrödinger equation (which are equivalent in the case of exact wave functions), the integral method is demonstrated to be intrinsically more accurate than the differential method. The variation principle for the marginal amplitude leads to a technique for improving approximate wave functions within a subspace of the whole configuration space. These concepts are illustrated by calculations on the ground state of the helium atom.
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    International Journal of Quantum Chemistry 21 (1982), S. 1123-1125 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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    International Journal of Quantum Chemistry 22 (1982), S. 217-217 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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    International Journal of Quantum Chemistry 22 (1982), S. 253-263 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: On the basis of the Heisenberg equation of motion and the Linderberg-Seamans approximations, useful formulas for, β-resonance integrals in the all-valence NDO-like semiempirical methods have been derived. The case of s, p, d basis sets of atomic orbitals has been considered.
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    International Journal of Quantum Chemistry 22 (1982), S. 293-298 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The calculations of long-range interaction energy are often based on multipole expansion. The truncated multipole expansion and interaction energy calculated with it are noninvariant with respect to an arbitrary choice of local coordinate systems. In this paper we show that truncated multipole expansion of form Σk = 1n CkR-k is “numerically” independent on a choice of local coordinate systems, if convergence conditions are satisfied.
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    International Journal of Quantum Chemistry 22 (1982), S. 31-36 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A model of vibronic coupling of crude Born-Oppenheimer (CBO) potentials within the scope of the linear variational procedure is presented. First numerical results testing the model are discussed.
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    International Journal of Quantum Chemistry 22 (1982), S. 183-190 
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    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Operator Ω and reaction operator T of Löwdin are studied with a slightly different approach, which leads to a clearer understanding of their nature and brings out the relevance of the conditions for the invertibility of K studied in the preceding work in this series.
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    International Journal of Quantum Chemistry 22 (1982), S. 385-395 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A method is formulated for enumerating and constructing isomerization reactions of molecules exhibiting large amplitude nonrigid motions. This method not only enumerates the isomers of nonrigid molecules and the corresponding rigid molecules but also the symmetry species spanned by the equivalent structures whose representative is an isomer. Consequently, using the method of correlating the symmetry species of a group to the symmetry species of its subgroup the splitting patterns of isomers of nonrigid molecule to those of rigid molecule are obtained. This provides an elegant method for both enumerating and constructing reaction graphs. The method is illustrated with examples.
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    International Journal of Quantum Chemistry 22 (1982), S. 429-431 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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    International Journal of Quantum Chemistry 22 (1982), S. 443-443 
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    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
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    International Journal of Quantum Chemistry 22 (1982), S. 537-545 
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    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Enzymes are large aperiodic structures and this hinders both ab initio molecular orbital and Bloch-type band theory of calculations. A frontier orbital perturbation theory of catalysis is applied to enzymes. Reasons are given for proposing that the induced-fit conformational changes, essential to enzymatic catalysis, leads to an increase in the electronic eigenvalue density at the active site, enhancing the necessary catalytic orbital perturbation.
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    International Journal of Quantum Chemistry 22 (1982), S. 199-215 
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    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A procedure is given to derive an explicit charge-transfer contribution from the Murrell-Randic-Williams formula, and to implement it in the framework of an additive procedure for the computation of intermolecular interaction energies, as a sum of electrostatic, repulsion, polarization, dispersion, and charge-transfer terms. Comparisons are performed between the radial and angular dependence of this term in model hydrogen-bonded systems, and that of the charge-transfer term resulting from SCF supermolecule computations. The evolution of the derived term can be matched very satisfactorily to that of an SCF counterpart when the counterpoise correction is taken into account. The underlying features governing the radial and angular evolution of the counterpoise and charge transfer terms are underlined.
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  • 154
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    International Journal of Quantum Chemistry 22 (1982), S. 435-440 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 155
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    International Journal of Quantum Chemistry 22 (1982), S. 441-441 
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    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 156
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    International Journal of Quantum Chemistry 22 (1982), S. 459-484 
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    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A generalization of the Hartree-Fock molecular orbital (MO) theory for treating diradical intermediates was explained pictorially by drawing molecular orbitals of diradical species such as ring-opened trimethylene. The generalized MO theory applied to elucidate electronic mechanisms of concerted, ionic, radical, and ion-radical reactions of organic reactants in the ground state. Generalized MO computations revealed the most essential characteristics of these reactions and mutal relationships between the worlds of Woodward-Hoffmann and Hughes-Ingold. Generalized MO studies supported our orbital symmetry, stability and pairing rules for concerted, ionic and radical reactions in the ground state, respectively. An extension of MO treatments to excited states reactions was briefly pointed out in relation to the density and spin correlation functions by the multireference CI wave functions.
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  • 157
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    International Journal of Quantum Chemistry 22 (1982), S. 547-556 
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    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The nonplanarity of a peptide unit has been studied by the ab initio method (GAUSSIAN 76) considering both the pyramidal structure of nitrogen and the variation of the ω angle for the N-methyl-acetamide and N-ethyl-acetamide in their cis and trans conformations. Several semiempirical methods have also been used for the sake of completeness of this work. All methods except CNDO and PCILO support a nonpyramidal structure for the nitrogen. The distortions of the planarity of the peptide unit show for both cis and trans conformations of the model compounds a significant asymmetric shift of the minimum on the energy curve for the ω rotation.
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  • 158
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    International Journal of Quantum Chemistry 22 (1982), S. 595-630 
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    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Seventeen different computer experiments are presented and analyzed. In each experiment a three-turn B-DNA double helix fragment interacts with a variable number of water molecules (from 60 to 1200), with a variable number of sodium ions (from 30 to 63), at one or more temperatures (280, 300, 320 K). The experiments are performed with the Monte Carlo method using quantum-mechanically derived potentials. In the analysis of the experiments we partition the water molecules (and the corresponding interactions) as being either bound or in the first solvation shell or in the groove regions relative to DNA; for the former two cases, the number of water molecules and the water interaction energy are reported for selected atoms or groups of atoms. The entire study is condensed into eight tables. The use of these tables is exemplified by considering, in detail, some of the trends emerging from these experiments. The analyses are complemented by graphical representations presented either to elucidate the very complex pattern of hydrogen bonded water molecules, or to show the statistical distributions of the oxygen and hydrogen atoms of the water molecules.
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  • 159
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    International Journal of Quantum Chemistry 22 (1982), S. 1059-1082 
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    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A theory is outlined of the nature and origin of drug-induced visual hallucination patterns. It is shown that such patterns correspond to blobs or stripes of visual neo-cortical activity. A neuronal circuit is described that generates such patterns whenever its homogeneous resting state becomes unstable. Such a process is shown to be an example of spontaneous symmetry-breaking, similar to that occurring in electro-weak interactions, and in fluid convection. It is suggested that the neuronal instability is produced by the action of hallucinogens on monoamine secreting brain-stem neurons.
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  • 160
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    International Journal of Quantum Chemistry 22 (1982), S. 1085-1152 
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    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Techniques of diagrammatic spin algebra are employed to derive segment factorization formulas for spin-adapted matrix elements of one- and two-electron excitation operators. The spin-adapted basis is formed by the Yamanouchi-;Kotani geneological coupling method, and therefore constitutes an irreducible basis of the unitary group U(N), as prescribed by Gel'fand and Tsetlin. Several features distinguish this paper from similar work that has recently been published. First, intermediate steps in the derivation of each segment factor are fully documented. Comprehensive tables list the spin diagrams and phases that contribute to the possible segment factors. Second, a special effort has been made to distinguish between those parts of a segment factor that can be ascribed to a spin diagram and those parts which arise from the orbitals. The results of this paper should thus be useful for those who wish to extend diagrammatic spin algebra to evaluation of matrix elements for states built from nonorthogonal orbitals. Third, a novel graphical method has been introduced to keep track of phase changes that are induced by line up permutations of creation and annihilation operators. This technique may be useful for extension of our analysis to higher excitations. The necessary concepts of second quantization and diagrammatic spin algebra are developed in situ, so the present derivation should be accessible to those who have little prior knowledge of such methods.
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  • 161
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    International Journal of Quantum Chemistry 22 (1982), S. 1221-1247 
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    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The correlation of the K-region carcinogenicity indices of Pullman and of Mainster and Memory with bay-region carbocation delocalization energy (BCDE) is displayed and shown to be maintained at the perturbational molecular orbital (PMO) level. PMO algebraic relations are examined to reveal the underlying relationships. Some correlation between BCDE and K-region indices exists simply because carbocation formation occurs preferentially on carbons which are bonded to positions α (adjacent) to ring fusion centers. Sampling a K region is synonymous with sampling such α carbons. However PMO analysis shows that a very strong correlation exists between BCDE and indices for a certain type of K region (called “primitive”). It is further shown that high BCDE is favored by a straight-line chain of benzene rings as one moves away from the bay region. Kinks in the chain will lower the BCDE, and the closer the kink is to the bay region, the greater is its effect. Effects of methylation upon BCDE are shown to correlate with K-region indices if the methylation occurs at a carbon which is in the opposite class as the carbon to which the bay-region carbocation is attached.
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  • 162
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    International Journal of Quantum Chemistry 21 (1982), S. 69-92 
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    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Instead of the Schródinger equation HΨ = EΨ subject to the boundary condition 〈ϕ|Ψ〉 = 1, where ϕ is a normalized reference function in the Hilbert space, one studies the inhomogeneous equation (H - E)ΨE = aϕ, where E is a complex variable, with the same boundary condition, which gives a = 〈ϕ|H|ΨE〉 - E = E1 - E. Introducing the projector P = 1 - |ϕ〉〈ϕ| for the complement to O = |ϕ〉〈ϕ|, one finds easily the explicit solution ΨE = (1 - PH/E)-1ϕ = (1 + TEH)ϕ, where TE = (E - PH)-1P = P(E - PHP)-1P is the reduced resolvent associated with the auxiliary Hamiltonian H̄ = PHP. The existence of these operators is discussed. It is shown that, if the parameter E is real in the “discrete part” of the spectrum to H, then E and E1 = 〈ϕ|H|ΨE〉 = 〈ϕ|H + HTEH|Φ〉 ≡f(E) bracket a true eigenvalue E satisfying the relation E = f(E). The Newton-Raphson solution to the equation F(E) = E - f(E) = 0 is related to the variation principle. Putting H = H0 + V and expanding the inverse (E - PH0 - PV)-1 in terms of powers of V or (V - α), one gets various expansions relating to finite-order perturbation theory. Exact expressions for the ordinary wave and reaction operators are obtained. If A is an arbitrary nonsingular operator and h = {h1,h2,…,hn} is a linearly independent set, the inner projection Án = |h〉 〈h|A-1|h〉-1〈h| is a “rational approximation” to the operator A which converges toward A when n→∞ and the set h becomes complete. If A is positive (or has a finite negative part) the convergence is from below. Applying this principle to the partitioning technique, one gets rational perturbation approximations instead of the standard power series, similar to the Padé approximants but derived in a different way with the remainder term under control. The method has been used to calculate lower bounds to eigenvalues.
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    International Journal of Quantum Chemistry 21 (1982), S. 125-131 
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    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The wave function for hydrogen in the Stark effect (or for the negatively anharmonic oscillator) with an outgoing-wave boundary condition, constructed in Langer-Cherry fJWKB form, is continued back to the origin. The asymptotic expansions for ReE and ImE are determined by the requirement that the wave function be regular at the origin to zeroth and first order in the exponentially small parameter that characterizes ImE. One fJWKB function turns out to be the Rayleigh-Schrödinger perturbation theory wave function.
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    International Journal of Quantum Chemistry 21 (1982), S. 173-177 
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    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: It is shown that the renormalization group imposes severe restrictions on analytic continuation in coupling constant in the case of field theories in four dimensions.
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    International Journal of Quantum Chemistry 21 (1982), S. 215-215 
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    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 166
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    International Journal of Quantum Chemistry 21 (1982), S. 251-258 
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    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A practical scheme for the calculation of excited states of the same symmetry as a given reference state is outlined in the context of the Hartree-Fock method. In order to prevent the excited state from “collapsing” into a lower-lying state, the prediagonalized Fock matrix is diagonalized in a restricted subspace, deleting the component associated with the orbital which participates in the excitation. Computationally, the deletion is accomplished by means of a “big shift” of the associated diagonal element of the prediagonalized Fock matrix. The resulting wave function will not be fully relaxed, but can be shown to be orthogonal to the reference state. The method has been implemented in a molecular UHF program. Applications to the 4σg-1 hole state of CO and to an excited state of the CuCl42- ion are reported.
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    International Journal of Quantum Chemistry 21 (1982), S. 357-357 
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    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 168
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    International Journal of Quantum Chemistry 21 (1982), S. 399-410 
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    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Using the variational principle, equations have been obtained for density matrix of molecules with the external perturbation of the common type present. The perturbed wave function was taken as a superposition of the ground and single-excited configurations made of the Hartree-Fock molecular spin orbitals. On the basis of these equations a series of variants of static perturbation theory have been worked out for the ground and excited states of closed-shell molecules.
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  • 169
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    International Journal of Quantum Chemistry 21 (1982), S. 465-473 
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    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: CI calculations were performed on the energies and relative intensities of the outer and inner valence levels of the CS molecule. Breakdown of the one-particle model is discussed in terms of CI, and the results are compared with the analogous investigations using the Green's function technique.
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  • 170
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    International Journal of Quantum Chemistry 21 (1982), S. 565-579 
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    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: We have employed an effective potential and a single-zeta basis in SCF-MO computations to estimate the relative stability of linear disilyne HSiSiH and five isomeric structures defined in earlier all-electron ab initio SCF-MO computations. The effect of electron correlation has been estimated by generalized valence-bond (GVB) computations for the five valence electron pairs of these structures. All our computations indicate that linear disilyne is the least stable structure and that H2SiSi, the silicon analog of vinylidene carbene, is the most stable structure. In these structures silicon occurs in divalent and tetravalent states. The nature of silicon bonding in these valence states is illustrated by contour diagrams of the GVB orbital pairs.
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    International Journal of Quantum Chemistry 21 (1982), S. 581-590 
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    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A method is developed for obtaining the spectra of trees of NMR and chemical interests. The characteristic polynomials of branched trees can be obtained in terms of the characteristic polynomials of unbranched trees and branches by pruning the tree at the joints. The unbranched trees can also be broken down further till we obtain a tree containing just two vertices. This effectively reduces the order of the secular determinant of the tree we started with to determinants of orders atmost equal to the number of vertices in the branch containing the largest number of vertices. An illustrative example of a NMR graph is given for which the 22 × 22 secular determinant is reduced to determinants of orders atmost 4 × 4 in just the second step of the algorithm. The tree pruning algorithm can be applied even to trees with no symmetry elements and such a factoring can be achieved. Methods developed here can be elegantly used to find if two trees are cospectral and to construct cospectral trees.
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    International Journal of Quantum Chemistry 21 (1982), S. 633-645 
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    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: An effective Hamiltonian for open-shell molecular systems is constructed. The unrestricted Hartree-Fock orbitals are applied as a basis set of one-particle functions. This effective Hamiltonian is determined as a simple product of the original total Hamiltonian and the spin annihilator. The second-quantization formalism and the Feynman-Goldstone diagrammatic technique are used. The resulting effective hamiltonian is composed of zero- to four-particle terms. A possibility of applying the nondegenerate diagrammatic perturbation theory constructed over this effective Hamiltonian is discussed.
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  • 173
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    International Journal of Quantum Chemistry 21 (1982), S. 673-676 
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    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The energy of a linearly perturbed enclosed system is calculated by way of the hypervirial methodology in the semiclassical limit. Solutions of this equation are compared with the exact as well as with WKB approximate results for the harmonic oscillator model.
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  • 174
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    International Journal of Quantum Chemistry 21 (1982), S. 717-726 
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    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: How the monotonic trend on which the periodicity of the periodic system is superposed is well described by Thomas-Fermi theory is explained. The mathematical structure of the periodicity is elucidated and explained. Algebraic formulas for the key atomic numbers are derived, e.g., the atomic number at which l electrons first appear is given by Zf(l) = 4 (∑n=0l n2)+1.
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  • 175
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    International Journal of Quantum Chemistry 21 (1982), S. 753-765 
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    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: We derive basic integrals needed for calculation of matrix elements of the Fourier transformed Coulomb operator and the Fourier transformed square of the Coulomb operator between 1s Slater functions. These integrals arise, for example, in the momentum space (k space) susceptibility formulation of van der Waals forces. The advantages of integration in k space (rather than r space) are that in k space there is a drastic reduction in the number of integration variables, and contour integration can be used. The derivation is completely analytic and the auxiliary integrals are all obtained in closed form.
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    International Journal of Quantum Chemistry 21 (1982), S. 799-811 
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    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Uniform quality basis sets (UQ-NG; N=3, 4, 5), with s = p and s ≠ p, and a 6-31 G* basis set have been optimized for the sulfur atom. These uniform quality basis sets in their uncontracted and contracted forms were used, together with other basis sets reported in the literature (a total of 40 basis sets), to study their accuracy in predicting the bond length and bond angle of H2S.
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    International Journal of Quantum Chemistry 21 (1982), S. 845-849 
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    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Relaxed orbital binding energies of electrons in zinc and cadmium are calculated using a relativistic local density functional theory. The discrepancy between our calculated binding energies and those from gas phase experimental data are attributed to inhomogeniety and many body effects.
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    International Journal of Quantum Chemistry 21 (1982), S. 861-874 
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    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: An analysis of the electronic correlation structures by means of the charge and spin correlation functions is carried out for full CI wave functions of four, five, and six membered conjugated π systems described by the Pariser-Parr-Pople Hamiltonian. The low-lying states of these systems are classified as covalent (CV) and ionic (IN) states depending on whether the probability of finding two electrons simultaneously at the same position is small or large. It is found that many of excited CV states, the typical ones of which are the 21Ag state of linear π systems, have stronger CV character than the ground CV state, and their spin coupling structures are different from each other as well as from that of the ground CV state. The spin coupling structure in the ground CV state has an “antiferromagnetic” spin arrangement in favor of antiparallel coupling between nearest neighbor spins while in excited CV states the extent of the antiparallel spin coupling between nearest neighbor sites is decreased. IN states, which are less common for low-lying states than CV ones, are also found to have characteristic modulations in the charge correlation. In particular, the charge correlations in the lowest singlet IN states, 11Bu of linear π systems, 11B2g of cyclobutadiene and 11B1U of benzene, are alternating.
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    International Journal of Quantum Chemistry 21 (1982), S. 875-884 
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    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: New formal results regarding the hypervirial analysis of enclosed systems are given. Novel applications are presented and several previous equations are reformulated in a more appropriate form.
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    International Journal of Quantum Chemistry 21 (1982), S. 917-926 
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    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: It is shown how the cluster CPA can be used to obtain the local density of states p(E) in a half-infinite or infinite random polymer chain. Calculations were performed for p(E) in a system composed of two coupled random chains with nearest neighbors interaction.
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    International Journal of Quantum Chemistry 21 (1982), S. 941-941 
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    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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    International Journal of Quantum Chemistry 21 (1982), S. 939-940 
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    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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    International Journal of Quantum Chemistry 21 (1982), S. 1003-1017 
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    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A systematic permutation-group approach for both the classification and description of the Feynman-Goldstone diagrams is presented. It allows us to “algebraize” the topological concepts and notions of many-body diagrammatic techniques, for example, the connectivity and disconnectivity of diagrams, the automorphism of a diagram, etc.
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  • 184
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    International Journal of Quantum Chemistry 21 (1982), S. 1029-1040 
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    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: In the active site of lactate dehydrogenase important roles are given to aminoacids His195 and Arg171. The coenzyme nicotinamide adenine dinucleotide (NAD) is required in oxidized form (NAD+) for the enzymatic oxidation of the substrate L-lactate. Molecular orbital methods CNDO/2, INDO, and EHT were applied to the study of the model of active center of lactate dehydrogenase. An energetically preferred arrangement of the models of His195, Arg171, NAD+, and lactate was found. Possible biochemical aspects of these arrangements are discussed.
    Additional Material: 8 Ill.
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  • 185
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    International Journal of Quantum Chemistry 21 (1982), S. 1061-1078 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The system of time-dependent Hartree-Fock equations allowing the calculation the of nth harmonic generation is established by using the same method used in a former paper in the same conditions. These equations are still subjected to orthonormalization conditions. Then by using a recurrence method, we express these equations in matrix form, as well as the orthonormalization conditions; and, as in the former paper, we then replace the solution of the matrix equation subjected to a constraint by that of a free equation. Finally the elimination of the spin variables allows a further simplification. So we obtain an equation allowing the calculation of the nth harmonic generation.
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  • 186
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    International Journal of Quantum Chemistry 21 (1982), S. 1105-1115 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The INDO-SCF method is used to provide electronic indices which are used as independent variables. These attempt to account for the variation in the antitumor activity and toxicity observed within a series of analogs of cis-diamino dichloro platinum(II).
    Additional Material: 1 Ill.
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  • 187
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The formalism for a configuration interaction approach is presented, in which explicit introduction of interelectronic coordinates into individual configurations is accomplished through the use of spherical Gaussian correlation factors. Formulas for all required matrix elements over these configurations are derived, and a computationally convenient algorithm to evaluate the matrix elements is presented. In addition, analysis of the form of the correlation factor shows that both angular and radial correlation can be obtained using spherical Gaussian correlation factors.
    Additional Material: 1 Ill.
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  • 188
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Theoretical computations are performed with the stacking interactions of the 2-naphthylnitrenium ion, the ultimate metabolite of 2-naphthylamine and N-hydroxy-2-naphthylamine, with guanine and adenine. The most stable stacked complex of guanine with this compound is found to be distinctly more stable than that of adenine. The optimized stacking interaction of guanine with 1-naphthylnitrenium ion yields an energy close to that with 2-naphthylnitrenium. By contrast, the dinucleoside monophosphate cytidyl-(3′-5′)-guanosine held in two preselected intercalated conformations is seen to favor 2-naphthylnitrenium over 1-naphthylnitrenium by a significant amount of energy. The possible relevance of this finding to explain the difference in adduct formation with guanine in DNA by the isomeric naphthylnitrenium ions is discussed.
    Additional Material: 6 Ill.
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  • 189
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    International Journal of Quantum Chemistry 22 (1982), S. 101-114 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Electronic energy level set topologies in the abstract nuclear charge space Z of molecular systems are defined and analyzed. Two theorems, one on the general convexity of level sets in Z, another on homotopies of boundaries of level sets, induced by nuclear geometry variations in the nuclear configuration space R, are proven. The applications of the two theorems are illustrated by examples of various molecules and ions.
    Additional Material: 2 Ill.
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  • 190
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    International Journal of Quantum Chemistry 22 (1982), S. 149-168 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The general extended geminal model is reviewed and two new approximate models EXGEM2 and EXGEM3 are introduced. In a test calculation on water using a double-zeta basis set, the approximate models recover 93.4% of the full CI correlation energy defined within the same basis set. A test calculation on the neon atom demonstrates that the performance of the models in comparison with the full CI, will improve as the basis set is increased. It is suggested that for basis sets of moderate and large size, and which include polarization functions, the extended geminal models are likely to recover 95%-97% of the correlation energy obtainable by the full CI.
    Additional Material: 3 Tab.
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  • 191
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    International Journal of Quantum Chemistry 22 (1982), S. 219-219 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 192
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    International Journal of Quantum Chemistry 22 (1982), S. 223-239 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A complete list of expressions is given covering all possible types of nontrivial two-body operator matrix elements in the unitary group approach. The matrix elements are expressed in terms of factors which depend on the unique spin coupling chain indicated by each Weyl tableau. The method applies equally to pure and mixed orbital configurations. The results extend and clarify previous general treatments of Drake and Schlesinger and Paldus and Boyle. We worked out two examples of 3(ƒ4) matrix elements of V4. V4 interaction and of 4(ƒ5)→4([2(ƒ3)]d2) matrix elements of V1 · V1 interaction.
    Additional Material: 3 Ill.
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  • 193
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    International Journal of Quantum Chemistry 22 (1982), S. 275-288 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: We present the first application of the coordinate rotation method, within the time-dependent Hartree-Fock framework, to calculation of positions and widths of metastable excited states. The method is briefly outlined and results of its application to 1P excited states of Li- are given. Comparison of our results to those obtained using electron scattering methods by other workers is also made.
    Additional Material: 3 Ill.
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  • 194
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    International Journal of Quantum Chemistry 22 (1982), S. 331-350 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A complete permutational analysis of the XeF6 dynamics is presented. The Longuet-Higgins group for each mode of rearrangement is obtained. On the basis of the splitting scheme of rigid molecule levels and statistical weights and selection rules for the non rigid molecule levels, it appears that transverse digonal twists and turnstile mechanisms have the same spectroscopic effects as the BPR-6 mechanisms. Hence, the previous interpretation of IR and Raman spectra is consistent with tunneling through transverse digonal twists and turnstile mechanisms as well as through BPR-6.
    Additional Material: 6 Ill.
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  • 195
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    International Journal of Quantum Chemistry 22 (1982), S. 397-414 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: We show that spin projected unrestricted-Hartree-Fock (PUHF) wave functions are able to well approximate some low-lying covalent states of ring π systems. The UHF wave functions belong to either the axial or torsional spin density wave class. Their spin structures are found to be approximations for the spin correlation structures of the corresponding exact wave functions. The PUHF wave functions become close to exact eigenstates with homopolar valence bond characters in the strong correlation limit.
    Additional Material: 2 Ill.
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  • 196
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    International Journal of Quantum Chemistry 22 (1982), S. 433-434 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 197
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    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 22 (1982) 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 198
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    International Journal of Quantum Chemistry 22 (1982), S. 485-496 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The detailed consideration of the kinetic aspect of the bridge process has allowed us to correctly write a kinetic equation beginning with knowledge of system microparameters. The solution of the equations makes it possible to elucidate the character of the relaxation process and to determine its typical constants as functions of those microparameters. Particular attention was given to kinetics in the presence of polaron effects. In this case the standard perturbation theory applied to derive the kinetic equations is not valid. The solutions obtained for this case are different both in the form of correlation functions and in the character of the interaction taken into account.
    Additional Material: 1 Ill.
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  • 199
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    International Journal of Quantum Chemistry 22 (1982), S. 557-573 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Addition and subtraction operators defined on some subspaces of the full CI space are introduced. It is shown that the effect of these operators on Löwdin many-electron wave functions consists in adding or removing an electron without destroying spin symmetry. Upward and downward recurrence relations for the Sanibel-type coefficients are presented. A strategy for employing the Löwdin functions for the matrix element evaluation and some special decomposition of the fermion creation-annihilation operators are discussed.
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  • 200
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    International Journal of Quantum Chemistry 22 (1982), S. 631-637 
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Several configurations of the C2H4 · HF molecular complex were studied using the 4-31G basis set. The most stable configuration was found to be the π hydrogen bonded complex. For this structure the interaction energy was computed employing a double-zeta basis plus polarization functions. The changes in electronic properties of the components C2H4 and HF due to complex formation were discussed.
    Additional Material: 3 Ill.
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