Nonlocal theory of dissociative electron attachment toH2and HF molecules

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We develop a method for calculation of dissociative electron attachment cross sections based on the Fano-Feshbach projection-operator approach. The coupling between the diabatic state and electron continuum is calculated with the inclusion of orthogonality scattering and long-range electron-molecule interaction. The dynamics of nuclear motion in the nonlocal complex potential is treated by semiclassical theory. We apply the theory to the calculation of dissociative attachment to the ${\mathrm{H}}_{2}$ and HF molecules. Our results for attachment to ground-state hydrogen molecules and the near-threshold vibrational enhancement of ${\mathrm{H}}_{2}$ are essentially the same as previous nonlocal results. However, the shape of the energy dependence of the cross section for attachment to vibrationally excited states of ${\mathrm{H}}_{2}$ is slightly different. The calculated value for the total attachment cross section to the ground state of HF is consistent with the little experimental data available; more definite conclusions are difficult because of the approximate nature of the experimental results. The results for the vibrational enhancement are in very good agreement with experiment.