Young-type interference pattern in molecular inner-shell excitations by electron impact

Recently, Tyliszczak et al. [J. Electron Spectrosc. Rel. Phenom. 114, 93 (2001)] have observed oscillations in the generalized oscillator strength (GOS) profile of molecular inner-shell excitations by electron impact. In order to check the mechanism that gives rise to these oscillations, we have calculated GOS profiles for different inner-shell{yields}Rydberg excitation processes in CO{sub 2} and butadiene. The comparison of the oscillations appearing in these ab initio results with a simple analytical model in which the interference term is explicit brings out very strong evidence favorable to the hypothesis that the observed oscillations in the GOS are due to Young-type quantum interference related to symmetry-equivalent atoms.