Configuration interaction study on the low-lying electronic states of strontium hydride cation including spin-orbit...

Ab initio calculations on low-lying electronic states of strontium hydride cations, SrH⁺, have been performed using the internally contracted multi-reference configuration interaction (icMRCI) method with Davidson correction (+Q). Spin-orbit coupling (SOC) effect between the singlet and triplet states of SrH⁺ has been investigated for the first time. The potential energy curves (PECs) of a total of 12 Λ-S states, as well as the 23 Ω states generated from the Λ-S states after considering the SOC effect, have been calculated. The spectroscopic constants and transition properties, including the transition dipole moments, the Franck-Condon factors, and the radiative lifetimes, have been obtained based on the calculated PECs. It indicates that the SOC effect plays a non-negligible role in electronic states of SrH⁺. Our study should shed light on the structure and behavior of low-lying electronic states and should pave further experimental studies on the spectroscopy of strontium hydride cations.