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

Abstract 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.