MRCI+Q study of the low-lying electronic states of CdF including spin-orbit coupling

CdF molecule, which plays an important role in a great variety of research fields, has long been subject to numerous researchers. Due to the unstable nature and heavy atom Cd containing in the CdF molecule, electronic states of the molecule have not been well studied. In this paper, high accurate ab initio calculations on the CdF molecule have been performed at the multi-reference configuration interaction level including Davidson correction (MRCI+Q). Adiabatic potential energy curves (PECs) of the 14 low-lying Λ-S states correlating with the two lowest dissociation limits Cd(¹S_g)+F(²P_u) and Cd(³P_u)+F(²P_u) have been constructed. For the bound Λ-S and Ω states, the dominant electronic configurations and spectroscopic constants are obtained，and the calculated spectroscopic constants of bound states are consistent with previous experimental results. The dipole moments (DMs) of ²Σ⁺ and ²Π are determined, and the spin-orbit (SO) matrix elements between each pair of X²Σ⁺, 2²Σ⁺, 1²Π, and 2²Π are obtained. The results indicate that the sudden changes of DMs and SO matrix elements arise from the variation of the electronic configurations around the avoided crossing region. Moreover, the Franck-Condon factors (FCFs), the transition dipole moments (TDMs), and radiative lifetimes of low-lying states-the ground state X²Σ⁺ are determined. Finally, the transitional properties of 2²Π-X²Σ⁺ and 2²Σ⁺-X²Σ⁺ are studied. Based on our computed spectroscopic information of CdF, the feasibility and challenge for laser cooling of CdF molecule are discussed.