Asymmetric electron localization in the single-photon dissociative ionization of H2

Abstract

By numerically solving the non-Born-Oppenheimer time-dependent Schr\"odinger equation of ${\mathrm{H}}_{2}$ in which the dynamics is confined along the laser polarization direction, we study the electron localization in the single-photon dissociative ionization of ${\mathrm{H}}_{2}$. The single ionization of ${\mathrm{H}}_{2}$ produces a free electron and ${\mathrm{H}}_{2}^{+}$, in whose later propagation the Coulomb field of the freed electron may excite ${\mathrm{H}}_{2}^{+}$ from the $1s{\ensuremath{\sigma}}_{g}$ state to $2p{\ensuremath{\sigma}}_{u}$ state. The mixture of these two states with opposite parities results in the asymmetric electron localization on the two nuclei after the dissociation of ${\mathrm{H}}_{2}^{+}$. The simulation result shows that the bound electron prefers being located on the nucleus, which propagates oppositely to the freed electron. The asymmetry parameter is larger if the freed electron has lower energy. The simulation results agree with experimental measurements in the full energy range. This study indicates that the correlation between ${\mathrm{H}}_{2}^{+}$ and the freed electron can be important and offers a perspective of controlling electron localization in chemical reactions.