Potential energies and cross sections for MgH+

Configuration-interaction (CI) potential curves have been calculated for the ten lowest singlet molecular states of MgH+. The X 1Σ, A 1Σ, and B 1Pi molecular states are calculated to be bound by 1.93, 1.93, and 0.18 eV at equilibrium separations 3.16, 3.84, and 4.41a0, respectively. These potential-well characteristics are in reasonable accord with analyses performed on spectroscopic data. The CI potential curves were employed in a three-channel scattering calculation to estimate H++Mg electron-capture cross sections at velocities (0.1--1.4) x 108 cm/sec. Capture with excitation of the ion dominates with H+Mg+ (3p) being the major electron-capture channel at 1 x 108 cm/sec. At higher velocities, a classical-trajectory Monte-Carlo method was used to calculate both the electron-capture and impact-ionization across sections for the H++Mg collision pair. The calculated electron-capture cross sections are in reasonable agreement with the recent measurements of Morgan and Eriksen