An R-matrix with pseudo-state (RMPS) approach to the single photon double ionization and excitation of the He-like Li${}^{+}$ ion

Abstract

The success of the R-matrix with pseudo-state (RMPS) method to model single photoionization processes, benchmarked against dedicated synchrotron light source measurements, is exploited and extended to investigate, single photon double ionization cross-sections for the He-like, Li${}^{+}$ ion. We investigate these processes from both the ground state and the excited $1s2{\mathrm{s}}^{1,3}\mathrm{S}$ metastable levels of this He-like system. Comparisons of the results from the R-matrix plus pseudo-state (RMPS) method are made with other state-of-the-art theoretical approaches such as time-dependent close-coupling (TDCC), B-splines and the convergent close-coupling (CCC). Excellent agreement with various other theoretical approaches are achieved but differences occur which are high-lighted and discussed. For the ground state the peak of the cross section is $\sim$ 2 kilo-barns (Kb), that for the $1s2{\mathrm{s}}^1\mathrm{S}$ state is $\sim$ 6 Kb and $\sim$ 1 Kb for the corresponding $1s2{\mathrm{s}}^3\mathrm{S}$ state. All the cross sections for single photon double ionization are extremely small, being in the region of 2Kb -- 10 Kb, or less, rendering their experimental determination extremely challenging.

7 figures, accepted for publicatio in J. Phys. B: At. Mol. & Opt. Phys

References in corpus (4)

• The SSS phase of RS Ophiuchi observed with Chandra and XMM-Newton I.: Data and preliminary Modeling
• An X-ray WHIM metal absorber from a Mpc-scale empty region of space
• Electron-impact ionization of the metastable excited states of Li+
• One-photon double ionization of helium: a heuristic formula for the cross section

Cited by in corpus (2)

• Near--K-edge double and triple detachment of the F- negative ion: observation of direct two-electron ejection by a single photon
• A Relativistic Equation-of-motion Coupled-Cluster Investigation of the Trends of Single and Double Ionization Potentials in the He and Be Isoelectronic Systems