Alignment-Dependent Ionization of N$_2$, O$_2$, and CO$_2$ in Intense Laser Fields

TL;DR

This paper investigates how the ionization probabilities of N₂, O₂, and CO₂ molecules depend on their alignment in intense laser fields, using numerical solutions of the Schrödinger equation, and explains discrepancies for CO₂ with a new trapping effect.

Contribution

It provides a theoretical analysis of alignment-dependent ionization, compares results with experiments, and introduces a coherent core-trapping explanation for CO₂'s behavior.

Findings

Good agreement with experiments for N₂ and O₂.

Identifies limitations of single-active-electron models for CO₂.

Proposes a field-induced coherent core-trapping mechanism.

Abstract

The ionization probability of N$_2$, O$_2$, and CO$_2$ in intense laser fields is studied theoretically as a function of the alignment angle by solving the time-dependent Schr\"odinger equation numerically assuming only the single-active-electron approximation. The results are compared to recent experimental data [D.~Pavi{\v{c}}i{\'c} et al., Phys.\,Rev.\,Lett.\ {\bf 98}, 243001 (2007)] and good agreement is found for N$_2$ and O$_2$. For CO$_2$ a possible explanation is provided for the failure of simplified single-active-electron models to reproduce the experimentally observed narrow ionization distribution. It is based on a field-induced coherent core-trapping effect.