Single and triple differential cross sections for double photoionization ofH−

Abstract

The hydride anion ${\mathrm{H}}^{\ensuremath{-}}$ would not be bound in the absence of electron correlation. Since the double-photoionization process is exquisitely sensitive to electron correlation, one expects electron correlation effects to leave a strong signature on the double-ionization cross sections for ${\mathrm{H}}^{\ensuremath{-}}$. We present fully differential cross sections for the three-body breakup of ${\mathrm{H}}^{\ensuremath{-}}$ by single-photon absorption. The absolute triply and singly differential cross sections were obtained from ab initio calculations making use of exterior complex scaling within a discrete-variable-representation partial-wave basis. Results calculated at photon energies of 18 and $30\phantom{\rule{0.3em}{0ex}}\mathrm{eV}$ are compared with reported cross sections for helium calculated at $20\phantom{\rule{0.3em}{0ex}}\mathrm{eV}$ above the double-ionization threshold. These comparisons show a clear signature of initial-state correlations that differentiate the He and ${\mathrm{H}}^{\ensuremath{-}}$ cases.