Electron collisions with the BeH molecular ion in the R-matrix approach

The R-matrix method is used to study electron collisions with the BeH molecular ion. The diatomic version of the UK Molecular R-matrix codes is used and a configuration-interaction calculation is first performed for the BeH target to obtain its potential energy curves for 19 lowest singlet and triplet states. Scattering calculations are then done to yield excitation and rotational excitation cross sections in the energy range 0−14 eV. Additionally we also obtain bound states of BeH and their quantum defects at the BeH equilibrium bond length 2.5369a0 . Resonance positions and widths for Feshbach resonances in the e-BeH system are also obtained and presented at the equilibrium bond length 2.5369a0.