Near-threshold vibrational excitation of H2 by electron impact: An ab initio study

We present the results of a fully ab initio treatment of vibrational excitation of H2 by low-energy electron impact. The calculations are based on a variational treatment closely related to the complex Kohn method and employ a trial wave function that uses an accurate, correlated target state and exact vibrational wave functions. Non-adiabatic vibrational effects are incorporated by using and off-shell T-matrix formalism. Our cross sections are in good agreement with recent crossed-beam measurements and are substantially larger than the values deduced from swarm data