Spectroscopic and transition properties of strontium chloride

The spectroscopic and transition properties of strontium chloride (SrCl) are investigated based on the theoretical approach of ab initio quantum chemistry. The calculation accuracy is improved by introducing Davidson correction, core-valence correlation (CV), the scalar relativistic and spin–orbit coupling (SOC) effects. The results show that the spectroscopic constants of X²Σ⁺ and A²Π states are consistent with the experimental results. The spectroscopic and molecular constants of most highly excited electronic states are reported for the first time. The permanent dipole moment (PDMs) and the spin–orbit (SO) matrix element have a sudden change for the avoidance of crossing. The potential energy curves (PECs) of the 14 Λ–S states split into 30 Ω states. The splitting energy of A²Π is 290.76 cm⁻¹, which has a little difference from the experimental value 295.597 cm⁻¹. Finally, the transition properties are given, including transition dipole moment (TDMs), Franck–Canton factor (FCFs) and radiation lifetime. It is found that the calculated radiation lifetime is in the order of 10 ns. The research will provide a theoretical reference for the feasibility of laser cooling of SrCl molecule. The dataset that supported the findings of this study is available in Science Data Bank, with the link https://www.doi.org/10.57760/sciencedb.j00113.00218.