Electronic structure of LaO based on frozen-core four-component relativistic multiconfigurational quasidegenerate perturbation theory

摘要

The electronic structure of the LaO molecule is studied using frozen-core four-componentmulticonfigurational quasidegenerate perturbation theory. The ground state and nine experimentallyobserved excited states are examined. The ground state is ~2Σ_(1/2)~+and its gross atomic orbital population is La5p~(5.76)6s~(0.83)6p~(0.14)p~(*0.21)d~(*1.17)f~(*0.26).O(2p~(4.630), wherep~*, d~*,andf~*are the polarizationfunctions of La that form molecular spinors with 0 2ps. We found that it is not necessary to considerthe excitation from the 0 2p electrons when analyzing the experimental spectra. This validates thefoundation of the ligand field theory on diatomic molecules, including the La atom where only oneelectron is considered. The spectroscopic constants Re, we, and To calculated for the ground state andlow-lying excited states A ' (~2Δ_(3/2)), A '(~2Δ_(5/2)) A(~2П_(1/2_),and A(~3/are in good agreement with theexperimental values.