The low-lying electronic states of BeCl: Potential energy curves, transition moments, transition probabilities, and radiative lifetimes

High-level CASSCF/MRCI calculations with a quintuple-zeta quality basis set are reported characterizing a manifold of electronic states of the BeCl correlating with the two lowest-lying dissociation channels. A very reliable picture of the potential energy curves showing regions of both avoided and curve crossings over a wide range of internuclear distances and the associated spectroscopic parameters provide new data that can help better rationalize the transitions so far observed. Our calculations suggest that the assignments and data for the band system C (2)Sigma(+)-X (2)Sigma(+) warrant new experimental studies. In fact we show that the C (2)Sigma(+) state (B (2)Sigma(+) in the experimental paper) has a double minimum. Also spin-orbit effects on the A (2)Pi state are shown to be relatively small. For the first time, transition moment functions for the major transitions are reported in the literature and used to estimate transition probabilities and radiative lifetimes. (c) 2013 Elsevier Inc. All rights reserved.