Ionisation of H2 in intense ultrashort laser pulses: parallel versus perpendicular orientation

Abstract

A theoretical comparison of the electronic excitation and ionisation behaviour of molecular hydrogen oriented either parallel or perpendicular to a linear polarised laser pulse is performed. The investigation is based on a non-perturbative treatment that solves the full time-dependent Schrödinger equation of both correlated electrons within the fixed-nuclei approximation and the dipole approximation. Results are shown for two different laser pulse lengths and intensities as well as for a large variety of photon frequencies starting in the one- and reaching into the six-photon regime. In order to investigate the influence of the intrinsic diatomic two-centre problem even further, two values of the internuclear separation and a newly developed atomic model are considered.