Characterization of Molecular Breakup by Very Intense Femtosecond XUV Laser Pulses

TL;DR

This paper investigates how super-intense femtosecond XUV laser pulses cause molecular breakup, revealing nonresonant dissociation dominance and proposing a model to predict control over vibrational and dissociation outcomes.

Contribution

It introduces a simple physical model based on field-dressed potential energy curves to explain and predict molecular dissociation mechanisms under intense XUV laser pulses.

Findings

Nonresonant dissociation channels can dominate over ionization.

The proposed model predicts vibrational excitation and dissociation yields.

Energy sharing between electrons and nuclei is characterized in the joint spectrum.

Abstract

We study the breakup of $\text{H}_2^+$ exposed to super-intense, femtosecond laser pulses with frequencies greater than that corresponding to the ionization potential. By solving the time-dependent Schr\"odinger equation in an extensive field parameter range, it is revealed that highly nonresonant dissociation channels can dominate over ionization. By considering field-dressed Born-Oppenheimer potential energy curves in the reference frame following a free electron in the field, we propose a simple physical model that characterizes this dissociation mechanism. The model is used to predict control of vibrational excitation, magnitude of the dissociation yields, and nuclear kinetic energy release spectra. Finally, the joint energy spectrum for the ionization process illustrates the energy sharing between the electron and the nuclei and the correlation between ionization and dissociation processes.