Model core potentials of p-block elements generated considering the Douglas–Kroll relativistic effects, suitable for accurate spin-orbit coupling calculations

Abstract

Model core potentials with scalar-relativistic effect at the third order Douglas-Kroll level combined with the first-order Douglas-Kroll for spin-orbit coupling are developed for the 25 p-block elements, B-Tl, with the valence space starting at (n-1)p(n-1)d, except group 13, where (n-1)s is also included because its importance was clearly demonstrated for Tl. All of the comparisons between model core potential and all-electron calculations of atomic and ionic term and level energies and the spectroscopic constants of monohydrides and cationic dimers indicate the chemical accuracy of our new potentials in reproducing all-electron properties. The applications of the new potentials to the cationic dimers show that polyatomic calculations with model core potential atoms are accurate. The periodic trends in the spectroscopic properties of cationic dimers and hydrides are discussed. The timing study demonstrates the extent of the computational savings. These new sets of model core potentials and basis sets, which we call ZFKn-DK3, have been implemented in the the widely used quantum chemistry program package GAMESS-U.S.

Performance of dynamically weighted multiconfiguration self-consistent field and spin-orbit coupling calculations of diatomic molecules of Group 14 elements

“…Using both SA-and DW-MCSCF orbitals at the correlation level of MCQDPT should bring about similar results, as Table I and Fig. Our experience with the SOC calculations 10,14,17 indicates that the inclusion of dynamic correlation is necessary to reproduce experimental data and to predict experimentally unknown data accurately. Our experience with the SOC calculations 10,14,17 indicates that the inclusion of dynamic correlation is necessary to reproduce experimental data and to predict experimentally unknown data accurately.…”

Effects of Spin–Orbit Coupling on Covalent Bonding and the Jahn–Teller Effect Are Revealed with the Natural Language of Spinors

“…A similar investigation is also performed for Tl 2 . For computational efficiency, we employed our newly developed ZFK3 model core potential and basis set for Tl, and the spin–orbit effect in this potential is at the level of DKH1. , The active space includes six orbitals with two electrons distributed among them. CASSCF geometry optimization for the first 1 ∑ g + term gives the equilibrium internuclear distance of 3.507 Å.…”

Analytic gradient and molecular dynamics simulations using the fragment molecular orbital method combined with effective potentials

“…MCP can be generated for heavy atoms using high level relativistic calculations [87]. A combined FMO and MCP method (FMO/MCP) has been developed by Ishikawa et al and applied to hydrated Hg 2?…”