Ab-initio study of the electronic structure of LaF including spin-orbit coupling

J Mol Model. 2022 May 26;28(6):170. doi: 10.1007/s00894-022-05157-0.

Abstract

Spectroscopic investigation of lanthanum monofluoride molecule LaF is carried out by ab-initio methods and all the observed band systems are predicted through the fine structure of LaH. This structure consisted of 67 Ω(±) states is calculated by taking into account the spin-orbit coupling effect of lanthanum. Therefore, these Ω(±) states are degenerated from 33 low-lying 1,3Λ(±) states below 33,200 cm-1. The potential energy curves (PECs) of 1,3Λ(±) and Ω(±) states are displayed in the range of internuclear distance from 1.40 to 3.00 Å and their spectroscopic constants ([Formula: see text],[Formula: see text], [Formula: see text], [Formula: see text]) are reported. Moreover, the permanent and the transition dipole moments are plotted as a function of internuclear distance. Furthermore, the composition of the Ω(±) state-wave functions in terms of Λ-S parent states is calculated at the equilibrium internuclear distance of the ground state. Furthermore, through calculating the splitting energy between the spin-orbit components of a 3Λ(±) state, Hund's case of many states involved in the observed band systems is determined.

Keywords: (2 s+1)Λ(±) states; LaF; SOC effect; Spectroscopic constants; Ω(±) states.