Electron energy spectra of H{sup {minus}} autodetaching states resulting from collisions of H{sup {minus}} with He at 1 keV

Electron energy spectra for H{sup {minus}} autodetaching states resulting from collisions H{sup {minus}} with He at 1 keV are rigorously calculated by including couplings between doubly excited states and continuum states and their interference with direct detachment processes. An energy sampling procedure, based on the Gauss quadratures, is used to discretize continuum states. The present theoretical result, for the first time, clarifies mechanisms of excitation to doubly excited states, quantitatively reproduces the experimental spectra first observed by Risley and Geballe in 1974, separates the contributions from each of three autodetaching states, and identifies the cause of the interference between autodetaching and direct-detaching excitation channels