Transition moment function, transition probabilities, and radiative lifetimes in the A 1Π–X 1Σ+ system of the CS molecule

Very accurate potential energy curves for the X 1Σ+ and A 1Π states of the CS molecule are reported using the CASSCF/MRSDCI approach. A theoretical description of the transition moment function of the X 1Σ+–A 1Π system over a large interval of internuclear distances is also presented which discloses relevant features about this function as yet unsuspected experimentally. Emission probabilities data also provide a trustful description of the relative intensities, and the radiative lifetimes are certainly a good reference for comparison with experimentally unperturbed results. For the A 1Π(v′=0, J′=1) state this work estimates an unperturbed radiative lifetime of 167 ns.