Electron-impact study of AlH using theR-matrix method

Abstract

We have carried out a comprehensive study of electron-impact on AlH molecule using the $R$-matrix method. Elastic (integrated and differential), momentum-transfer, excitation, and ionization cross sections along with rate coefficients have been presented at various levels of approximation. The target states are represented by including correlations via a configuration-interaction technique. The results of the static-exchange, one-state, and 20-state close-coupling approximations are presented. Our study has detected Feshbach and core-excited shape resonances in 20-state model. We detect a stable bound state of ${\text{AlH}}^{\ensuremath{-}}$ having configuration $1{\ensuremath{\sigma}}^{2}2{\ensuremath{\sigma}}^{2}3{\ensuremath{\sigma}}^{2}4{\ensuremath{\sigma}}^{2}1{\ensuremath{\pi}}^{4}5{\ensuremath{\sigma}}^{2}2\ensuremath{\pi}$ with a vertical electronic affinity value of 0.22 eV which is in good agreement with the estimated experimental value of about 0.15 eV. The ionization cross sections are calculated in binary-encounter-Bethe model in which Hartree-Fock molecular orbitals are used to calculate kinetic and binding energies of the occupied molecular orbitals.