iSURF: A family of infinite-time surface flux methods

TL;DR

This paper introduces a new family of surface flux methods for calculating photoelectron spectra from wave functions, enabling fully-converged results at the end of laser pulses with reduced computational demands.

Contribution

It presents a novel family of infinite-time surface flux methods based on analytical Volkov continuation, improving PES extraction efficiency and accuracy.

Findings

Allows fully-converged PES at the end of laser pulses

Reduces computational demands compared to previous methods

Implemented in a TDSE solver for practical use

Abstract

The computation and analysis of photoelectron spectra (PES) is a fundamental technique in atomic and molecular physics to study the structural and dynamical properties of a target system, and to gain insight into the process of its ionization. Since the first numerical solutions of the time-dependent Schr\"odinger equation, numerous methods have been developed to extract PES from the calculated wave functions. However, most of these methods have severe limitations or are computationally very demanding. Here we present a new family of methods, based on the ideas of the so-called analytical Volkov continuation, or time-dependent surface flux ([Ermolaev, A. M. et al. Phys. Rev. A 60, 4831 (1999), Ermolaev, A. M. et al. Phys. Rev. A 62, 015401 (2000), Tao L. and Scrinzi A. New Journal of Physics 14, 013021 (2012)]), that allows one to obtain fully-converged PES at the end of the laser pulse using either Volkov states or the exact scattering-states, and that has been implemented in the Time Dependent Schr\"odinger Equation (TDSE) solver ([Patchkovskii S. and Muller H. G., Computer Physics Communications 199, 153 (2016)]).