Ab initio configuration interaction study on the energetics and electronic structure of the 1-52Σ+ and 1-32Πstates of CS+

The energetics and electronic structure of the 1-52Σ+ and 1-32Π states of CS+ at and around the equilibrium internuclear distance Re for the CS X1Σ+ state are studied by carrying out ab initio configuration interaction (CI) calculations. The spectroscopic constants of Te, ωe, and Re for the 1-42Σ+, 12Π, and 32Π states are evaluated from the CI potential energy curves (PECs). The avoided crossing between the 2-32Σ+ PECs causes the 32Σ+ minimum and explains the observed high intensities for the photoionization from the CS X1Σ+ state to both the 2-32Σ+ states. The avoided crossing between the 3-42Σ+ PECs produces the 32Σ+ maximum and 42Σ+ well minimum. The avoided crossing between the 2-32Π PECs results in the 32Π minimum and a small minimum spacing (0.14 eV) between the PECs.