Frustrated double ionization in two-electron triatomic molecules

TL;DR

This study uses a semi-classical model to analyze frustrated double ionization in D3+ molecules under intense laser fields, revealing pathway dominance shifts and identifying observable fragment angular distributions.

Contribution

It introduces a detailed semi-classical approach to FDI in triatomic molecules and distinguishes the dominant ionization pathways as laser intensity varies.

Findings

Good agreement between model and experimental kinetic energy release data.

Over-the-barrier ionization surpasses tunnel ionization at higher field strengths.

Identified a unique angular distribution feature as a signature of a specific FDI pathway.

Abstract

Using a semi-classical model, we investigate frustrated double ionization (FDI) in $\mathrm{D_3^+}$, a two-electron triatomic molecule, when driven by an intense, linearly polarized, near-infrared (800 nm) laser field. We compute the kinetic energy release of the nuclei and find a good agreement between experiment and our model. We explore the two pathways of FDI and show that, with increasing field strength, over-the-barrier ionization overtakes tunnel ionization as the underlying mechanism of FDI. Moreover, we compute the angular distribution of the ion fragments for FDI and identify a feature that can potentially be observed experimentally and is a signature of only one of the two pathways of FDI.