Electro-nuclear dynamics of single and double ionization of H$_2$ in ultrafast intense laser pulses

TL;DR

This paper introduces an efficient semi-analytical and numerical method to model single and double ionization of H$_2$ molecules in ultrafast intense laser pulses, accounting for vibrational dynamics and predicting ionization probabilities and product energies.

Contribution

The paper presents a novel combined semi-analytical and numerical approach for modeling molecular ionization and vibrational dynamics in strong laser fields, enabling accurate predictions with limited computational resources.

Findings

Vibrational dynamics significantly influence ionization yields.

The method accurately predicts dissociative ionization and Coulomb explosion energies.

The approach is computationally efficient across various laser parameters.

Abstract

We present an efficient method for modeling the single and double ionization dynamics of the H$_2$ molecule in ultrashort intense laser fields. This method is based on a semi-analytical approach to calculate the time-dependent single and double molecular ionization rates and on a numerical approach to describe the vibrational motion that takes place in the intermediate molecular ion H$_2^+$. This model allows for the prediction of the single and double ionization probabilities of the H$_2$ molecule to be made over a wide range of frequencies and laser intensities with limited computational time, while providing a realistic estimate of the energy of the products of the dissociative ionization and of the Coulomb explosion of the H$_2$ molecule. The effect of vibrational dynamics on ionization yields and proton kinetic energy release spectra is demonstrated and, in the case of the latter, discussed in terms of basic strong-field molecular fragmentation mechanisms.