Showing papers by "Yasuyuki Ishikawa published in 1993"
TL;DR: In this paper, a universal Gaussian basis set was developed for relativistic Dirac-Fock calculations on atoms and molecules, and the Dirac Fock energies computed by using this single set of the universal GAussian basis for the atoms, He ([ital Z]=2) through No ([italZ]=102), were in excellent agreement with the corresponding numerical finite-difference DiracFock method.
Abstract: A universal Gaussian basis set is developed for accurate [ital ab] [ital initio] relativistic Dirac-Fock calculations on atoms and molecules. The Dirac-Fock energies computed by using this single set of the universal Gaussian basis for the atoms, He ([ital Z]=2) through No ([ital Z]=102), are in excellent agreement with the corresponding numerical finite-difference Dirac-Fock method. The total Dirac-Fock energies for lighter atoms agree with the corresponding numerical limit to a part in 10[sup 9] and for heavier systems to a part in 10[sup 8]. The total energy for the heaviest system, No ([ital Z]=102), calculated with our universal Gaussian basis set differs from the corresponding numerical limit by only 4 mhartrees.
151 citations
TL;DR: A relativistic many-body perturbation theory based on the Dirac-Fock-Breit wave functions has been developed and implemented by employing analytic basis sets of Gaussian-type functions.
Abstract: A relativistic many-body perturbation theory based on the Dirac-Fock-Breit wave functions has been developed and implemented by employing analytic basis sets of Gaussian-type functions. The instantaneous Coulomb and low-frequency Breit interactions are treated using a unified formalism in both the construction of the Dirac-Fock-Breit self-consistent-field atomic potential and in the evaluation of many-body perturbation-theory diagrams. The relativistic many-body perturbation-theory calculations have been performed on the helium atom and ions of the helium isoelectronic sequence up to [ital Z]=50. The contribution of the low-frequency Breit interaction to the relativistic correlation energy is examined for the helium isoelectronic sequence.
34 citations
TL;DR: In this article, a universal Gaussian basis set was developed for ab initio relativistic Dirac-Fock calculations on atoms and molecules, and the results of the matrix Dirac−Fock-Coulomb and Dirac•Fock−Breit self-consistent field calculations using this basis set were presented for the atoms.
29 citations
TL;DR: In this article, a relativistic universal Gaussian basis set was developed for ab initio relatievistic Dirac-Fock-Coulomb and Dirac Fock-Breit self-consistent field calculations on heavy atoms.
25 citations
TL;DR: In this article, a universal Gaussian basis set (UGBSII) was proposed for ab initio relativistic Dirac-Fock calculations on atoms and molecules, and the Dirac Fock-Coulomb energies were obtained with this universal Gaussian basis set.
Abstract: A universal Gaussian basis set (UGBSII) is reported for ab initio relativistic Dirac–Fock calculations on atoms and molecules. The Dirac–Fock–Coulomb energies obtained with this universal Gaussian ...
18 citations
TL;DR: In this article, a semi-empirical model was employed to calculate the rotational state population distributions of diatomic photofragments from the photodissociation of isotopically variant triatomic molecules.
3 citations
TL;DR: This paper pointed out that the conclusion of the cited paper by Matsuoka is in agreement with that drawn in our earlier study in contrast to Matsuokas claim to the contrary.
3 citations
TL;DR: In this paper, the ground and low-lying excited state properties of the bimetallic Al 2 Na cluster were investigated using ab initio unrestricted Hartree-Fock and quadratic configuration interaction calculations with a 6-31 G* basis set.
2 citations