The electronic structure of the low lying sextet and quartet states of CrF and CrCl

The electronic structure of CrF and CrCl in X 6Σ+, 6Π, 6Δ, A6Σ+, 4Σ+, 4Π, and 4Δ states that correlate with the low lying 6S, 6D, and 4D states of Cr+ have been studied, using large atomic natural orbital (ANO) basis sets and a variety of ab initio methods, including multi-reference configuration interaction (MRCI) and coupled cluster with perturbative triples (RCCSD(T)). We include scalar relativistic effects perturbatively and also explore the consequence of correlating the 3s and 3p electrons on the transition metal. We report T e, R e,ωe, as well as dipole moments, bond energies, and charge distributions and compare with the available experimental data as well as previous theoretical results.