Configuration interaction study on low-lying states of AlCl molecule* *Project supported by the National Key Research and Development Program of China (Grant No. 2017YFA0403300), the National Natural Science Foundation of China (Grant Nos. 11874177, 11874179, and 11574114), the Natural Science Foundation of Jilin Province, China (Grant No. 20180101289JC), and the High Performance Computing Center of Jilin University and High Performance

Abstract

High-level ab initio calculations of the Λ–S states for aluminum monoiodide (AlCl) molecule are performed by utilizing the explicitly correlated multireference configuration interaction (MRCI-F12) method. The Davidson correction and scalar relativistic correction are investigated in the calculations. Based on the calculation by the MRCI-F12 method, the spin–orbit coupling (SOC) effect is investigated with the state-interacting technique. The adiabatic potential energy curves (PECs) of the 13 Λ–S states and 24 Ω states are calculated. The spectroscopic constants of bound states are determined, which are in accordance with the results of the available experimental and theoretical studies. Finally, the transition properties of 0+(2)–X0+, 1(1)–X0+, and 1(2)–X0+ transitions are predicted, including the transition dipole moments (TDMs), Franck–Condon factors (FCFs), and the spontaneous radiative lifetimes.