Radical SBr: A challenge to spectroscopists?

A theoretical description of the electronic states of the SBr radical at a high level of correlation effects treatment is presented for the first time. Most of its potential energy curves have a repulsive nature, but a set of bound Π 2 states should provide a means for the experimental characterization of this species. The ground state can support over 40 vibrational states, but transitions from the 2 Π 2 state, with a very shallow well (four levels), should have intensities spread over a maximum around v ″ = 10 ; lower vibrational levels can only be accessed for transitions from two high-lying Rydberg states. A whole set of spectroscopic constants, including vibrationally averaged spin-orbit coupling constants, and radiative transition probabilities and lifetimes quantify the theoretical description, thus supplying reliable results to guide the experimental investigation of this species.