Daniel A. Horner

First principles calculations of the double photoionization of atoms and molecules using B-splines and Exterior Complex Scaling

We report a fully ab initio implementation of exterior complex scaling in B‐splines to evaluate total, singly and triply differential cross sections in double photoionization problems. Results for He and H2 double photoionization are presented and compared with experiment.

Calculation of excitation‐autoionization of helium with three active electrons: Sharp Resonance features in the SDCS

A clear signature in the form of sharp features in the singly differential cross section for the (e,2e) process due to excitation of autoionizing states of helium is demonstrated in calculations in the S‐wave limit. All three active electrons are treated on the same footing in calculations using the exterior complex scaling (ECS) method that applies the correct outgoing boundary conditions for all the breakup channels in the problem. At the energies treated here, within a few eV of the threshold for the excitation‐autoionization process, the effects of post‐collision interactions are clearly demonstrated. It is suggested that such behavior should be seen generally in (e,2e) experiments on atoms that measure the single differential cross section.