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  • 1
    Electronic Resource
    Electronic Resource
    On the approximation of potential-energy functions for two-center systems (1978)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 13 (1978), S. 641-677 
    Details
    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: Let E(R) be a potential-energy function for a neutral or ionic diatom in the Born-Oppenheimer approximation. Then the approximation of E(R) for 0 〈 R 〈 ∞ starting from finite and typically small sets of given information is considered. The approach is based on the fact that the scaled potential curves F(R) = R2E(R) derive from an eigenvalue problem which depends linearly on R. The nature of the curves F(R) is examined in detail. The results include the discovery of various approximants, some of which display rigorous bounding properties and others, closely related, whose behavior with respect to the approximated function appears to be predictable.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560130509
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  • 2
    Electronic Resource
    Electronic Resource
    Usage de l'Algègbre de Lie su (n) Dans l'Etude des Systèmes Quantiques à n Etats. I. Quelques Conséquences Générales (1983)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 23 (1983), S. 1807-1816 
    Details
    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: In an n level quantum system there is a relation between each density operator and an element of su (n) Lie algebra. This relation is also established between Cartan's subalgebras and the complete sets of compatible observables. A scalar product is then defined in this algebra in order to introduce orthonormal bases and to simplify many calculations about expectation values of observables. Therefore simple general rules were established which show how to determine (completely or partly), from linearly independent observables, the density operator of the system.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560230510
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  • 3
    Electronic Resource
    Electronic Resource
    Usage de l'algkbre de lie su(n) dans l'etude des systèmes quantiques à n etats. III. Définition et obtention des constantes du mouvement conjoncturelles (1984)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 26 (1984), S. 479-488 
    Details
    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
    Description / Table of Contents: From the density operator, some constants of the motion are defined and established. We suggest calling them conjunctural constants of the motion. It is proved that no more than n - 1 of them can be linearly independent. Using su(m) (m 〈 n ) subalgebra associated with the Hamiltonian-operator, it is shown how conjunctural constants of the motion can be expressed in terms of the coherence vector components.
    Notes: A partir de I'opérateur-densité d'un système quantique à n états, sont définies et calcultes des constantes du mouvement pour lesquelles est proposée I'appellation nouvelle de conjoncturelles. On établit qu'il en existe au maximum n - 1 linéairement indépendantes. A I'aide des sous-algèbres su(m) (m 〈 n ), on montre comment il est possible d'introduire, suivant la forme de I'hamiltonien, des constantes du mouvement conjoncturelles reliées aux composantes du vecteur de cohérence.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560260406
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  • 4
    Electronic Resource
    Electronic Resource
    Dynamics of enzyme reactions in solution and in heterogeneous media (1984)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 26 (1984), S. 943-953 
    Details
    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: Enzymes are catalysts occurring in living cells. The aim of this paper is to describe some basic properties of enzymes and to understand on a physical basis how the intracellular milieu may control the kinetics of enzyme reactions. We shall therefore consider in succession some kinetic properties of enzymes in solution and the way cell surfaces and biological membranes control the dynamics of enzyme reactions. The choice of topics which have been selected in this paper is somewhat arbitrary and certainly reflects the tastes and the personal interests of the authors.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560260529
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  • 5
    Electronic Resource
    Electronic Resource
    Ab initio calculation of the heptamer (NH3)7 as a reasonable starting point for a description of the ammonia crystal (1983)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 24 (1983), S. 687-695 
    Details
    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: Quasi-Wannier functions for the ammonia crystal have been determined from optimized ab initio calculations of the heptamer (NH3)7, thus accounting for all the first neighbor interactions. The calculated geometry and binding energy are in good agreement with their experimental counterparts.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560240612
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  • 6
    Electronic Resource
    Electronic Resource
    The modeling of nucleophilic and electrophilic additions and substitutions using extended Hückel-based reaction potentials (1990)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 38 (1990), S. 623-640 
    Details
    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 new formalism has been developed in order to evaluate intermolecular interaction energies for organometallic complexes including electrostatic, polarization, and orbital contributions based on extended Hückel molecular orbital (EHMO) theory. The electrostatic interaction is evaluated using (i) a multipolar expansion of EHMO charge density, or (ii) by calculating directly the electrostatic integrals in the basis of atomic orbitals. The polarization effects are evaluated by introducing a perturbation into the Hamiltonian. The orbital interaction is calculated by considering a supermolecule made of the organometallic substrate and a model electrophile or nucleophile. To provide the shortest possible response time on an interactive computer graphics facility, this model should require the minimum amount of computer time, which explains why approximate procedures are used to evaluate the dominant contributions to the interaction energies. Preliminary results show that these interaction energies lead to reaction potentials in good agreement with experiment for a broad series of nucleophilic and electrophilic addition or substitution reactions involving organometallic complexes. In addition, it is shown that the method can easily be extended for the calculation of solvent effects. To this end, developments considering the supermolecule surrounded by a polarizable continuum are in progress.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560380505
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  • 7
    Electronic Resource
    Electronic Resource
    Simple derivation of conditions for instability in the Hartree-Fock and projected Hartree-Fock schemesA preliminary version of this paper has been circulating as Technical Note No. 517 from the Uppsala Quantum Chemistry Group. (1981)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 20 (1981), S. 1201-1215 
    Details
    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 conditions for instability of solutions of Hartree-Fock and projected Hartree-Fock equations are derived in a form involving finite real symmetric matrices. These conditions are also expressed in terms of the Fock-Dirac density matrix, both at the spin-orbital and at the orbital level. The particular variations which give rise to the so-called singlet and triplet instabilities are described.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560200605
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  • 8
    Electronic Resource
    Electronic Resource
    Usage de l'Algèbre de Lie su (n) dans l'Etude des Systèmes Quantiques à n Etats. II. Transformation de l'Espace des Observables, Problèmes d'Evolution (1983)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 23 (1983), S. 1817-1827 
    Details
    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: In the previous paper we examined, for a quantum system, the relation between its n-dimensional state space and the su (n) Lie algebra. The present paper is devoted to relations between unitary transformations in the state space and orthogonal transformations in Lie's algebra. Two cases can happen. First, the transformations are independently chosen in the two spaces; this amounts to changing the former relation. On the other hand, the relation is maintained and the unitary operators are then related to some of the orthogonal operators. This second case is used to study the evolution operators.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560230511
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  • 9
    Electronic Resource
    Electronic Resource
    Usage de l'Algèbre de Lie su (n) dans l'Etude des Systèmes Quantiques à n Etats. V. Application aux Systèmes composés (1985)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 28 (1985), S. 269-286 
    Details
    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
    Description / Table of Contents: We adapt the use of the Lie algebra su (n) we proposed in former papers to a system made up of two subsystems (respectively, nA and nB states). We show how reduced density operators, correlation problems, and overall and reduced evolution equations, may be made precise with this formalism.
    Notes: L'usage de l'algèbre de Lie su (n), proposé dans les articles précédents, est adapté a l'étude d'un système formé de deux sous-systèmes, respectivement à nA et nB états. On montre comment diverses notions (opérateurs-densités réduits, problèmes de corrélation, équations d'évolution globales et réduites) peuvent être précisées grâce au formalisme introduit.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560280209
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  • 10
    Electronic Resource
    Electronic Resource
    Usage de l'algèbre de lie SU(n) dans l'etude des systèmes quantiques a n etats. VII: Sur le “problème inverse” (1989)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 35 (1989), S. 331-337 
    Details
    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: Through a formalism developed in formr papers, some problems, set by the determination, from experimental data of the evolution equation of an n-states quantum system are considered.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560350210
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