Electron localization in dissociating $H_2^{+}$ by retroaction of a photoelectron onto its source

Abstract

We investigate the dissociation of $H_2^{+}$ into a proton and a $H^0$ after single ionization with photons of an energy close to the threshold. We find that the $p^{+}$ and the $H^0$ do not emerge symmetrically in case of the $H_2^{+}$ dissociating along the $1s\ddot{I}{ƒ}_g$ ground state. Instead, a preference for the ejection of the $p^{+}$ in the direction of the escaping photoelectron can be observed. This symmetry breaking is strongest for very small electron energies. Our experiment is consistent with a recent prediction by Serov and Kheifets [Phys. Rev. A 89, 031402 (2014)]. In their model, which treats the photoelectron classically, the symmetry breaking is induced by the retroaction of the long range Coulomb potential onto the dissociating $H_2^{+}$.

Accepted for publication in Phys.Rev.Lett. 1/11/2016