Intensity dependence of ionization mechanisms for infrared frequencies in the strong field double ionization of diatomic molecules

TL;DR

This study investigates how different ionization mechanisms in diatomic molecules respond to intense infrared laser pulses, revealing distinct signatures and structures related to electron interactions and recollision processes.

Contribution

It introduces a three-dimensional quasiclassical approach to analyze ionization pathways and identifies the origin of finger-like momentum structures in diatomic molecules.

Findings

Distinct ionization mechanisms have unique momentum signatures.

Finger-like structures are due to strong backscattering interactions.

The recollision process significantly influences ionization dynamics.

Abstract

Using a three-dimensional quasiclassical technique we explore the double ionization pathways of a diatomic molecule driven by an intense infrared (800nm) ultrashort laser pulse. For intensities corresponding to the tunneling regime, we find that the three main ionization mechanisms have distinct traces when considering the sum of the momenta parallel to the laser field as a function of the inter-electronic angle of escape. In addition, we find that the previously observed "finger-like" structure in the correlated momenta of the strongly driven He is also present for strongly driven diatomic molecules. We show that it is mainly due to the strong interaction, backscattering, the recolliding electron undergoes from the remaining core.