RELATIVISTIC QUANTUM-CHEMISTRY AND RIGOROUS VARIATIONAL ANALYSIS
DSpace at IIT Bombay
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Title |
RELATIVISTIC QUANTUM-CHEMISTRY AND RIGOROUS VARIATIONAL ANALYSIS
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Creator |
DATTA, SN
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Subject |
molecular-structure calculations
multiconfigurational dirac-fock cartesian gaussian functions effective core potentials many-electron atoms hartree-fock configuration-interaction pseudopotential approach expansion calculations 2-electron ions relativistic effects molecular calculations bounds min-max theorems quantum electrodynamics |
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Description |
A brief review of relativistic quantum chemistry is given here. Relativistic effects and their importance in chemistry are discussed. An outline of different theoretical aspects is presented. Aspects of variation techniques relevant to relativistic calculations are discussed in detail. These involve the derivation of min-max theorems for Dirac, Dirac-Hartree-Fock and Dirac-Coulomb calculations. The consequence of relativistic Hamiltonians being unbounded are also discussed for other lines of investigation. The upper bounds derived are physically interpreted. Sample Dirac-Hartree-Fock results for the Be atom, calculated using both STO and GTO bases for the nonrelativistic orbitals and the upper components of the relativistic orbitals, are given. The inadequacy of the so-called kinetically balanced basis set is discussed and illustrated with these results. The importance of the variational or dynamical balance and hence the merit of the LCAS-MS scheme is pointed out. The possibility of calculating quantum electrodynamical pair energy from relativistic configuration interaction calculations on a two-electron atom is discussed and exemplified. The present status of relativistic molecular calculations is briefly reviewed. Conclusions on the aspects of variational analysis and molecular calculations are enclosed.
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Publisher |
INDIAN ACADEMY SCIENCES
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Date |
2011-08-02T06:54:34Z
2011-12-26T12:53:45Z 2011-12-27T05:40:44Z 2011-08-02T06:54:34Z 2011-12-26T12:53:45Z 2011-12-27T05:40:44Z 1994 |
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Type |
Article
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Identifier |
PROCEEDINGS OF THE INDIAN ACADEMY OF SCIENCES-CHEMICAL SCIENCES, 106(2), 445-466
0253-4134 http://dspace.library.iitb.ac.in/xmlui/handle/10054/8699 http://hdl.handle.net/10054/8699 |
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Language |
en
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