Ionization behavior of molecular hydrogen in intense laser fields: Influence of molecular vibration and alignment

Abstract

The alignment- and internuclear-distance dependent ionization of H${}_2$ exposed to intense, ultrashort laser fields is studied by solving the time-dependent two-electron Schrödinger equation. In the regime of perturbative few-photon ionization, a strong dependence of the ionization yield on the internuclear distance is found. While this finding confirms a previously reported breakdown of the fixed-nuclei approximation for parallel alignment, a simpler explanation is provided and it is demonstrated that this breakdown is not due to vibrational dynamics during the laser pulse. The persistence of this effect even for randomly aligned molecules is demonstrated. Furthermore, the transition from the multiphoton to the quasi-static (tunneling) regime is investigated considering intense 800 nm laser pulses. While the obtained ionization yields differ significantly from the prediction of Ammosov-Delone-Krainov rates, we find a surprisingly good quantitative agreement after introducing a simple frequency-dependent correction to the standard tunneling formula.

arXiv comment10 pages, 9 figures

References in corpus (6)

• Alignment-Dependent Ionization of N${}_2$, O${}_2$, and CO${}_2$ in Intense Laser Fields
• Strong field ionization to multiple electronic states in water
• Alignment-Dependent Ionization of Molecular Hydrogen in Intense Laser Fields
• Ionisation of hydrogen molecule in intense ultrashort laser pulses: parallel versus perpendicular orientation
• A simple parameter-free one-center model potential for an effective one-electron description of molecular hydrogen
• Ionization of molecular hydrogen and deuterium by a frequency-doubled Ti:sapphire laser pulses

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• A Review on Ab Initio Approaches for Multielectron Dynamics
• Implementation of a time-dependent multiconfiguration self-consistent-field method for coupled electron-nuclear dynamics in diatomic molecules driven by intense laser pulses