Static coherent states method for investigating high-order harmonic generation in single-electron molecular systems

TL;DR

This paper introduces a static coherent states method for efficiently modeling high-order harmonic generation in single-electron molecules, demonstrating improved accuracy and reduced computational cost over traditional methods.

Contribution

The novel static coherent states approach enables accurate, low-cost simulations of nonlinear laser-molecule interactions, especially high-order harmonic generation, in full dimensional single-electron systems.

Findings

Enhanced harmonic accuracy through averaging over random simulations

Reduced basis set requirements compared to traditional solvers

Successful modeling of attosecond pulse generation using polarization gating

Abstract

In this report, a novel methodology based on the static coherent states approach is introduced with the capability of calculating various strong-field laser-induced nonlinearities in full dimensional single-electron molecular systems; an emphasis is made on the high-order harmonic generation. To evaluate the functionality of this approach, we present a case study of the Hydrogen molecular ion \ih interacting with a few-cycle linearly polarized optical laser with trapezoidal waveform. We detected that the accuracy of the obtained harmonics is considerably enhanced by averaging the expectation value of the acceleration of the single electron over a set of identical random simulations. Subsequently, the presented approach demands a significantly lower number of basis sets than the regular exact three dimensional unitary split-operator solvers of time dependent Schr{\"o}dinger equation that necessitate an extremely large number of data points in the coordinate space, and so the computational cost. Additionally, applying static coherent states method, we have investigated isolated attosecond pulse generation using the polarization gating technique, which combines two delayed counter rotating circular laser pulses, and opens up a gate at the central portion of the superposed pulse.