Double photoionization of aligned molecular hydrogen

Abstract

We present converged, completely ab initio calculations of the triple differential cross sections for double photoionization of aligned ${\mathrm{H}}_{2}$ molecules for a photon energy of $75.0\phantom{\rule{0.3em}{0ex}}\mathrm{eV}$. The method of exterior complex scaling, implemented with both the discrete variable representation and $B$-splines, is used to solve the Schr\"odinger equation for a correlated continuum wave function corresponding to a single photon having been absorbed by a correlated initial state. Results for a fixed internuclear distance are compared to recent experiments and show that integration over experimental angular and energy resolutions is necessary to produce good qualitative agreement, but does not eliminate some discrepancies. Limitations of current experimental resolution are shown to sometimes obscure interesting details of the cross section.