Relativistic fourcomponent staticexchange approximation for coreexcitation processes in molecules
Abstract
A generalization of the staticexchange approximation for coreelectron spectroscopies to the relativistic fourcomponent realm is presented. The initial state is a Kramers restricted HartreeFock state and the final state is formed as the configurationinteraction single excited state, based on the average of configurations for (n1) electrons in n neardegenerate core orbitals for the reference ionic state. It is demonstrated that the staticexchange Hamiltonian can be made real by considering a set of timereversal symmetric electron excitation operators. The staticexchange Hamiltonian is constructed at a cost that parallels a single Fock matrix construction in a quaternion framework that fully exploits timereversal and spatial symmetries for the D{sub 2h} point group and subgroups. The K and Ledge absorption spectra of H{sub 2}S are used to illustrate the methodology. The calculations adopt the DiracCoulomb Hamiltonian, but the theory is open ended toward improvements in the electronelectron interaction operator. It is demonstrated that relativistic effects are substantial for the Ledge spectrum of sulfur, and substantial deviations from the statistical 2:1 spinorbit splitting of the intensity distribution are found. The average ratio in the mixed region is 1.54 at the present level of theory.
 Authors:
 Department of Physics, Chemistry and Biology, Linkoeping University, SE581 83 Linkoeping (Sweden)
 (Italy)
 Publication Date:
 OSTI Identifier:
 20974564
 Resource Type:
 Journal Article
 Resource Relation:
 Journal Name: Physical Review. A; Journal Volume: 73; Journal Issue: 2; Other Information: DOI: 10.1103/PhysRevA.73.022501; (c) 2006 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA)
 Country of Publication:
 United States
 Language:
 English
 Subject:
 74 ATOMIC AND MOLECULAR PHYSICS; ABSORPTION SPECTRA; CONFIGURATION INTERACTION; CORRECTIONS; DIRAC APPROXIMATION; DISTRIBUTION; ELECTRON SPECTROSCOPY; ELECTRONELECTRON COUPLING; ELECTRONELECTRON INTERACTIONS; ELECTRONS; EXCITATION; EXCITED STATES; HAMILTONIANS; HARTREEFOCK METHOD; KRAMERSKRONIG CORRELATION; MATRICES; MOLECULES; RELATIVISTIC RANGE; SPIN; SYMMETRY
Citation Formats
Ekstroem, Ulf, Norman, Patrick, Carravetta, Vincenzo, and Istituto per i Processi ChimicoFisici, Area della Ricerca del C.N.R., via G. Moruzzi 1, I56124 Pisa. Relativistic fourcomponent staticexchange approximation for coreexcitation processes in molecules. United States: N. p., 2006.
Web. doi:10.1103/PHYSREVA.73.022501.
Ekstroem, Ulf, Norman, Patrick, Carravetta, Vincenzo, & Istituto per i Processi ChimicoFisici, Area della Ricerca del C.N.R., via G. Moruzzi 1, I56124 Pisa. Relativistic fourcomponent staticexchange approximation for coreexcitation processes in molecules. United States. doi:10.1103/PHYSREVA.73.022501.
Ekstroem, Ulf, Norman, Patrick, Carravetta, Vincenzo, and Istituto per i Processi ChimicoFisici, Area della Ricerca del C.N.R., via G. Moruzzi 1, I56124 Pisa. Wed .
"Relativistic fourcomponent staticexchange approximation for coreexcitation processes in molecules". United States.
doi:10.1103/PHYSREVA.73.022501.
@article{osti_20974564,
title = {Relativistic fourcomponent staticexchange approximation for coreexcitation processes in molecules},
author = {Ekstroem, Ulf and Norman, Patrick and Carravetta, Vincenzo and Istituto per i Processi ChimicoFisici, Area della Ricerca del C.N.R., via G. Moruzzi 1, I56124 Pisa},
abstractNote = {A generalization of the staticexchange approximation for coreelectron spectroscopies to the relativistic fourcomponent realm is presented. The initial state is a Kramers restricted HartreeFock state and the final state is formed as the configurationinteraction single excited state, based on the average of configurations for (n1) electrons in n neardegenerate core orbitals for the reference ionic state. It is demonstrated that the staticexchange Hamiltonian can be made real by considering a set of timereversal symmetric electron excitation operators. The staticexchange Hamiltonian is constructed at a cost that parallels a single Fock matrix construction in a quaternion framework that fully exploits timereversal and spatial symmetries for the D{sub 2h} point group and subgroups. The K and Ledge absorption spectra of H{sub 2}S are used to illustrate the methodology. The calculations adopt the DiracCoulomb Hamiltonian, but the theory is open ended toward improvements in the electronelectron interaction operator. It is demonstrated that relativistic effects are substantial for the Ledge spectrum of sulfur, and substantial deviations from the statistical 2:1 spinorbit splitting of the intensity distribution are found. The average ratio in the mixed region is 1.54 at the present level of theory.},
doi = {10.1103/PHYSREVA.73.022501},
journal = {Physical Review. A},
number = 2,
volume = 73,
place = {United States},
year = {Wed Feb 15 00:00:00 EST 2006},
month = {Wed Feb 15 00:00:00 EST 2006}
}

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