Single and triple differential cross sections for double photoionization ofH−

Abstract

The hydride anion H − would not be bound in the absence of electron correlation. Electron correlation drives the double photoionization process and, thus should impact double photoionization results most strongly for H − . We present fully differential cross sections for the three-body breakup of H − by single photon absorption. The absolute triple-differential and single-differential cross sections were yielded by ab initio calculations making use of exterior complex scaling within a discrete variable representation partial wave basis. Results calculated at photon energies of 18eV and 30eV are compared with reported cross sections for helium calculated at 20eV above the double ionization threshold. These comparisons show a clear signature of initial state correlation that differentiate the He and H − cases.

DoubleK-shell photoionization of atomic beryllium

“…The insensitivity of the beryllium cross sections at an energy closer to threshold for equal energy sharing is indicative of the diminished importance of angular correlation in the initial state relative to the dominant nuclear attraction potential for the 1s electrons in beryllium, which see a substantially larger effective Z initially than in the case of helium, where the angular distributions are more responsive to excess energies closer to threshold. This is consistent with previous results comparing TDCS angular distributions for helium and H − , where the initial state correlation represents an even more substantial contribution to the energetics than either target presently considered [15].…”

Triple differential cross sections and nuclear recoil in two-photon double ionization of helium

“…In these calculations we have used the numerical procedures and the representation of the wave functions previously utilized for both the H − anion [34] and molecular hydrogen [35] and decompose the full scattered wave into angular components on a radial grid in order to implement exterior complex scaling. Thus, we expand the scattered wave functions that solve Eqs.…”

“…Thus, we expand the scattered wave functions that solve Eqs. (3) and (4) in partial waves of the form The radial function ψ l1m1,l2m2 (r 1 , r 2 ) multiplying the product of spherical harmonics is taken to be a twodimensional finite element-discrete variable representation (FEM-DVR) function, as in references [35] and [34]. The FEM-DVR radial basis is an attractive choice because of the computational efficiency gained as well as its natural complementarity for implementing exterior complex scaling [36].…”

Cross sections for short-pulse single and double ionization of helium

“…We employ the same computational techniques here that we have used our recent work on two-electron problems [11,12]. The two-electron wave function is first expanded in products of spherical harmonics…”