Photoionization of few electron systems with a hybrid Coupled Channels approach

TL;DR

This paper introduces a hybrid coupled channels method combining quantum chemistry and strong-field dynamics to accurately compute photo-electron spectra of multi-electron systems under intense laser fields.

Contribution

The paper presents a novel hybrid anti-symmetrized coupled channels approach that unites electronic structure with strong-field dynamics for detailed photoelectron spectra calculations.

Findings

Method accurately reproduces spectra for helium, beryllium, and hydrogen molecule.

At long wavelengths, helium and hydrogen can be modeled as single-channel systems.

Beryllium requires a multi-channel description for accurate spectra.

Abstract

We present the hybrid anti-symmetrized coupled channels method for the calculation of fully differential photo-electron spectra of multi-electron atoms and small molecules interacting with strong laser fields. The method unites quantum chemical few-body electronic structure with strong-field dynamics by solving the time dependent Schr\"odinger equation in a fully anti-symmetrized basis composed of multi-electron states from quantum chemistry and a one-electron numerical basis. Photoelectron spectra are obtained via the time dependent surface flux (tSURFF) method. Performance and accuracy of the approach are demonstrated for spectra from the helium and berryllium atoms and the hydrogen molecule in linearly polarized laser fields at wavelength from 21 nm to 400 nm. At long wavelengths, helium and the hydrogen molecule at equilibrium inter-nuclear distance can be approximated as single channel systems whereas beryllium needs a multi-channel description.