Exploring excited electronic states: A theoretical contribution to the spectroscopy of strontium monochloride, SrCl

Abstract

The Λ + S and Ω electronic states of strontium monochloride are characterized at the CASSCF/MRCI+Q level of theory. For the first time, reliable potential energy curves and associated spectroscopic parameters, as well as dipole moment and transition dipole moment functions are reported. Transition probabilities given by the Einstein coefficients for spontaneous emission, and the associated radiative lifetimes provide relevant information on the relative intensities of the various bands systems. Accurate dissociation energies were determined for the ground and excited states, and a set of spin-orbit constants derived for the 2Π and 2Δ states. Electronic transitions involving a new bound state A´ 2Δ offer new routes to spectroscopic studies. Radiative lifetimes for the states A 2Π, B 2Σ+, and C 2Δ show good agreement with experimental ones. The suggestion in the literature of an avoided crossing involving the B 2Σ+ state to explain a local perturbation in the spectra is not corroborated in this study. The present results should provide a clear perspective to guide future experimental investigations of electronic transitions on this system.