GRECP/MRD-CI calculations of spin-orbit splitting in ground state of Tl and of spectroscopic properties of TlH

Abstract

The generalized relativistic effective core potential (GRECP) approach is employed in the framework of multireference single-and double-excitation configuration interaction (MRD-CI) method to calculate the spin-orbit (SO) splitting in the 2 P o ground state of the Tl atom and spectroscopic constants for the 0 + ground state of TlH. The 21-electron GRECP for Tl is used and the outer core 5s and 5p pseudospinors are frozen with the help of the level shift technique. The spin-orbit selection scheme with respect to relativistic multireference states and the corresponding code are developed and applied in the calculations. In this procedure both correlation and spin-orbit interactions are taken into account. A [4,4,4,3,2] basis set is optimized for the Tl atom and employed in the TlH calculations. Very good agreement is found for the equilibrium distance, vibrational frequency, and dissociation energy of the TlH ground state (R e = 1.870 Å, ω e = 1420 cm −1 , D e = 2.049 eV) as compared with the experimental data (R e = 1.868 Å, ω e = 1391 cm −1 , D e = 2.06 eV).SHORT NAME: GRECP/MRD-CI calculations on Tl and TlH

Theoretical study ofHfF+in search of the electron electric dipole moment

“…Details on features of constructing the reference space and selection procedure are given in Refs. [21,31,32].…”

“…Next, the spin-orbit direct configuration interaction (SODCI) approach [28,29,30] modified by our group to account for spin-orbit interaction in configuration selection procedure [31] with the selected single and double excitations from some multiconfigurational reference states ("mains") is employed on the sets of different ΛS many-electron spin-and space-symmetry adapted basis functions (SAFs). Details on features of constructing the reference space and selection procedure are given in Refs.…”

GRECP/5e‐MRD‐CI calculation of the electronic structure of PbH

“…) is approximately equal to 96% at the second run and to 98% at the third run for each of the considered states and internuclear distances of the PbH molecule (for more details, see paper by Mosyagin et al from the same volume and paper [5]). …”

“…A detailed description of the methods used in the present calculations can be found elsewhere [3,5,6]. Here we give only brief description and specifics of each method.…”

“…Our recent calculations [5] also show that the MRD-CI method with an improved selection scheme and properly chosen basis set enables one to reach a level of accuracy for molecular calculations involving heavy atoms which is comparable to the accuracy of the GRECP calculations for transition energies between electronic terms in those atoms.…”