Theoretical structure of the low lying electronic states of yttrium fluoride YF

A theoretical investigation of the lowest molecular states of YF has been performed via CASSCF and MRCI (single and double excitations with Davidson correction) calculations. Spin-orbit effects have been introduced through semi-empirical spin orbit pseudo-potential for yttrium while they have been neglected for fluorine. Potential energy curves for 20 electronic states in the representation 2S + 1Λ(±) (neglecting spin-orbit effects) and 41 electronic states in the representation Ω(±) (including spin-orbit effects) have been determined along with some corresponding spectroscopic constants. Comparison of the present results with available experimental one show an overall satisfying agreement. New results are produced for 7 states 2S + 1Λ(±) and their SO components, not yet observed.