Near-threshold electron impact dissociation of H2 within the adiabatic nuclei approximation

Abstract

At low energies, the major pathway for the electron-impact dissociation of H2 (e + H2 → H(1s) + H(1s)+ e) is through excitation to the b 3Σu+ dissociative state. We present ab initio calculations of the rate of dissociation as a function of initial vibrational level. The calculations employ an extension to the adiabatic nuclei approximation, balancing the energy between the electrons and the nuclei, for excitation to a dissociation continuum. We find that near-threshold rates show so strong a dependence on the initial H2 vibrational level that the common practice of approximating the total dissociation rate to the v = 0 rate is invalid in many situations.