Abstract

Using the graphical user interface GABEDIT and the computational chemistry software MOLPRO, the ab initio calculation method has been applied to explore 25 low-lying singlet and triplet electronic states, including the X¹Σ⁺ ground state, of the calcium sulfide molecule CaS in the ^2s+1Λ^± representation. The multi-reference configuration interaction with Davidson correction (MRCI+Q) and the complete active space self-consistent field (CASSCF) calculations were performed to obtain the potential energy curves in terms of the internuclear distance R. The permanent dipole moments μ_e of these low-lying electronic states of CaS have been investigated, in addition to the corresponding spectroscopic constants (including the electronic energy with respect to the ground state T_e, the equilibrium internuclear distance R_e, the harmonic vibrational frequency ω_e, the rotational constant B_e, and the equilibrium dissociation energy D_e). In the present work, 19 new singlet and triplet CaS electronic states were investigated for the first time. In addition, it is noticeable that the current results and those already available in literature are in good agreement.

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