Laser-assisted multiphoton ionization of a hydrogen atom by electron impact

TL;DR

This paper theoretically investigates how intense laser fields influence the multiphoton ionization of hydrogen by electron impact, revealing significant laser modifications in cross sections that align with recent experiments but challenge existing theories.

Contribution

It provides a detailed theoretical analysis of laser-assisted multiphoton ionization, highlighting effects not captured by first-order theories and comparing results with recent experimental data.

Findings

Laser significantly enhances the binary peak in TDCS.

Results agree qualitatively with recent experiments.

Contradicts predictions of existing first-order theories.

Abstract

The dynamics of the electron impact multiphoton ionization of a hydrogen atom in the presence of an intense laser field has been studied theoretically, with a view to comparing (qualitatively) the results with the recent kinematically complete experiments of Horr et al [ Phys. Rev. Lett., vol. 94, 153201, (2005) ] for the He target. Significant laser modifications are noted in the present doubly (DDCS) and the fully differential cross sections (TDCS). For most of the explored kinematics (chosen in accordance with the experiment), the present binary peak intensity of the laser-assisted TDCS is significantly enhanced with respect to the field free ones, in agreement with the experiment but in contradiction with the existing first order theories. Importance of the multiphoton effects are also studied.