Charge-transfer cross sections and mobilities for Hg+ ions in atomic mercury

Abstract

By treating the mercury atomic ion and the mercury atom as one-electron and two-electron systems respectively, and employing the Coulomb approximation to derive the atomic orbitals, the interaction energies between a Hg+ ion and a Hg atom at large nuclear separations have been calculated for the 2Σu ground state and the 2Σg repulsive state of the Hg2+ molecular ion. These interaction energies have then been used to calculate semi-classical approximation phase shifts for the elastic scattering of Hg+ ions by Hg atoms, from which resonance charge-transfer and diffusion cross sections have been derived. Comparison is made with the results of calculations employing cruder approximations and with the rather meagre experimental data on charge transfer. Finally, the diffusion cross sections have been used to calculate the mobility of Hg+ ions in atomic mercury as a function of temperature. The theoretical mobility curve corresponding to the Coulomb approximation atomic orbitals lies somewhat above the rather uncertain experimental data.