LAUSR

The multi-reference configuration interaction method plus Davidson correction (MRCI+Q) are adopted to study the low-lying states of SH with consideration of scalar relativistic effect, core-valence (CV) electron correlation, and spin–orbit coupling (SOC) effect. The SOC effect on the low-lying states is considered by utilizing the full Breit–Pauli operator. The potential energy curves (PECs) of 10 Λ–S states and 18 Ω states are calculated. The dipole moments of 10 Λ–S states are calculated, and the variation along the internuclear distance is explained by the electronic configurations. With the help of calculated SO matrix elements, the possible predissociation channels of A2Σ+, c4Σ− and F2Σ− are discussed. The Franck–Condon factors of A2Σ+–X2Π, F2Σ−–X2Π and E2Σ+–X2Π transitions are determined, and the radiative lifetimes of A2Σ+ and F2Σ− states are evaluated, which are in good agreement with previous experimental results.