Two-photon Double Ionization of H$_2$ in Intense Femtosecond Laser Pulses

TL;DR

This paper presents ab initio calculations of two-photon double ionization cross sections for molecular hydrogen under intense femtosecond laser pulses, providing detailed insights into electron correlations and response.

Contribution

It introduces a fully nonperturbative, time-dependent approach using prolate spheroidal coordinates to accurately model molecular double ionization dynamics.

Findings

Results align between previous theoretical studies

Highlights importance of experimental conditions for comparison

Provides detailed angular and energy-resolved ionization data

Abstract

Triple-differential cross sections for two-photon double ionization of molecular hydrogen are presented for a central photon energy of 30 eV. The calculations are based on a fully {\it ab initio}, nonperturbative, approach to the time-dependent Schroedinger equation in prolate spheroidal coordinates, discretized by a finite-element discrete-variable-representation. The wave function is propagated in time for a few femtoseconds using the short, iterative Lanczos method to study the correlated response of the two photoelectrons to short, intense laser radiation. The current results often lie in between those of Colgan {\it et al} [J. Phys. B {\bf 41} (2008) 121002] and Morales {\it et al} [J. Phys. B {\bf 41} (2009) 134013]. However, we argue that these individual predictions should not be compared directly to each other, but preferably to experimental data generated under well-defined conditions.