Improved Lewenstein model for high-order harmonic generation of atoms and molecules with scattering wavefunctions

TL;DR

This paper introduces an improved Lewenstein model for high-order harmonic generation that incorporates scattering wavefunctions, leading to more accurate spectra aligned with quantum calculations, especially for molecules.

Contribution

The authors replace plane waves with scattering waves in the Lewenstein model, enhancing its accuracy for HHG spectra prediction.

Findings

HHG spectra match well with time-dependent Schrödinger equation results

The method improves quantitative predictions for molecular high harmonic generation

Scattering wavefunctions provide better recombination matrix elements

Abstract

We demonstrate a simple method to improve the Lewenstein model for the description of high-order harmonic generation (HHG). It is shown that HHG spectra can be expressed as the product of a returning electron wave packet and the photo-recombination cross sections, where the former can be extracted from the Lewenstein model. By replacing plane waves with scattering waves in the calculation of recombination matrix elements, we showed that the resulting HHG spectra agree well with those from solving the time-dependent Schr\"odinger equation. The improved model can be used for quantitative calculations of high harmonics generated by molecules.