Ionization Suppression of Diatomic Molecules in Intense Midinfrared Laser Field

TL;DR

This study investigates the suppressed ionization of diatomic molecules like O₂ in intense midinfrared laser fields, revealing the role of two-center interference through experimental data and S-matrix theory calculations.

Contribution

It clarifies the mechanism behind molecular ionization suppression, emphasizing the significance of two-center interference effects, supported by experimental and theoretical analysis.

Findings

O₂ shows wavelength and intensity-dependent ionization suppression

S-matrix theory accurately reproduces experimental results

Two-center interference is key to understanding suppression

Abstract

Diatomic molecules (e.g., O$_2$) in intense laser field exhibit a peculiar suppressed ionization behavior compared to their companion atoms. Several physical models have been proposed to account for this suppression while no consensus has been achieved. In this letter, we aim to clarify the underlying mechanisms behind this molecular ionization suppression. Experimental data recorded at midinfrared laser wavelength and its comparison with that at near-infrared wavelength revealed a peculiar wavelength and intensity dependence of the suppressed ionization of O$_2$ with respect to its companion atom of Xe, while N$_2$ behaves like a structureless atom. It is found that the S-matrix theory calculation can reproduce well the experimental observations and unambiguously identifies the significant role of two-center interference effect in the ionization suppression of O$_2$.