Showing papers by "Yasuyuki Ishikawa published in 1992"
TL;DR: In this article, a Dirac-Fock self-consistent field scheme for open-shell molecules is implemented in terms of the generalized coupling operator formalism and the method is applied to the ground state Γ 1 2 of the AuH + ion in order to evaluate the effects of relativity on chemical bonding of this species.
12 citations
TL;DR: In this article, a universal Gaussian basis set (18s, 12p, 11d) was used for the Dirac-Fock-Coulomb and Dirac Fock-Breit self-consistent field calculations.
Abstract: Matrix Dirac–Fock–Coulomb and Dirac–Fock–Breit self-consistent field calculations are performed for a number of neutral atoms. He (Z = 2) through Xe (Z = 54), using the universal Gaussian basis set (18s, 12p, 11d) reported recently by Da Silva etal. The total Dirac–Fock–Coulomb, the Dirac–Fock–Breit, and the Breit interaction energies calculated with this universal Gaussian basis set are in good agreement with the corresponding values obtained by using an extensive well-tempered Gaussian basis set for the He through Ca (Z = 20) atoms. Although this universal Gaussian basis set is inadequate for the calculation of total Dirac–Fock–Coulomb and Dirac–Fock–Breit energies for the Kr, Sr, and Xe atoms, the Breit interaction energies calculated with this basis for these three atoms are in very good agreement with the corresponding Breit interaction energies obtained by using the extensive well-tempered Gaussian basis sets. Work is in progress to generate a more extensive and energetically better universal Gaussi...
10 citations
TL;DR: In this paper, a number of Dirac-Fock-Breit calculations were performed on heavy atoms up to Rn using large geometric basis sets Gaussian-type functions.
6 citations
TL;DR: In this article, the relativistic many-body perturbation theory calculations on Xe have been performed with basis sets of well-tempered Gaussian-type functions of Huzinaga and Klobukowski.
Abstract: Relativistic many-body perturbation theory calculations on Xe have been performed with basis sets of well-tempered Gaussian-type functions of Huzinaga and Klobukowski. The well-tempered Gaussian-type functions were used in both contracted and uncontracted form. The contracted Gaussian basis sets used in the relativistic many-body study are designed to retain flexibility for correlated calculations both in the core and the valence region. They reproduce second-order energy corrections computed with uncontracted Gaussian basis sets to an accuracy of greater than 99%. A compact representation of the relativistic wave functions in terms of contracted well-tempered Gaussian functions used in the present study provides a useful means of curtailing integral storage requirements and the time needed for correlated calculations, while still retaining high accuracy in relativistic electron correlation effects. Keywords: Dirac–Fock, relativistic many-body perturbation theory, well-tempered Gaussian basis, xenon.
6 citations
TL;DR: In this article, a detailed study of the pair correlation energies in Xe was done in order to analyze the nature of relativistic and correlation effects in this heavy-atom system, and the Dirac-Fock, SCF, and many-body perturbation calculations were performed by employing analytic basis sets of well-tempered GAUSSIAN-type functions.
Abstract: Relativistic pair correlation energies of Xe were computed by employing a partial-wave expansion up to order Lmex = 5. The Dirac-Fock (DF), SCF, and many-body perturbation calculations were performed by employing analytic basis sets of well-tempered GAUSSIAN-type functions. A detailed study of the pair correlation energies in Xe is done in order to analyze the nature of relativistic and correlation effects in this heavy-atom system. © 1992 John Wiley & Sons, Inc.
1 citations