The p-H symmetry breaking in dissociative ionization of H2 due to the molecular ion interaction with the ejected electron

Abstract

We propose a novel mechanism of electron localization and molecular symmetry breaking in dissociative photoionization of the H$_2$ molecule. The Coulomb field of the ejected electron can induce transition of the remaining H$_2^+$ ion from the gerade $^2\Sigma_g^1(1s\sigma_g)$ to the ungerade $^2\Sigma_u^1(2p\sigma_u)$ electronic state when the nuclei in a bound vibrational state are near the outer turning point. The superposition of this process with a direct transition to vibrational continuum should produce a non-gerade ionic state which results in observed asymmetry in the $p$-H ejection relative to the electron ejection direction at a small kinetic energy release.