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

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 ( R e , T e , ω e , ω e χ e ) 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. [ABSTRACT FROM AUTHOR]