A theoretical investigation of the low-lying electronic states of the molecule BeH

A theoretical study at the multireference singles and doubles configuration-interaction level is reported for the six lowest electronic states of BeH+. Of the four new states described, the 1Π and 3Π are bound states supporting at least 8 and 12 vibrational levels, respectively. Two 3Σ+ states are repulsive. For the two known 1Σ+ states improved results are also presented. For all these states, dipole moments and transition moments have been computed. For the bound states, besides the vibrational levels, transition probabilities, radiative lifetimes, vibrationally averaged dipole moments, and a set of spectroscopic constants are also reported.