Transient spectroscopy from time-dependent electronic-structure theory without multipole expansions
Abstract
Based on the work done by an electromagnetic field on an atomic or molecular electronic system, a general gauge invariant formulation of transient absorption spectroscopy is presented within the semi-classical approximation. Avoiding multipole expansions, a computationally viable expression for the spectral response function is derived from the minimal-coupling Hamiltonian of an electronic system interacting with one or more laser pulses described by a source-free, enveloped electromagnetic vector potential. With a fixed-basis expansion of the electronic wave function, the computational cost of simulations of laser-driven electron dynamics beyond the dipole approximation is the same as simulations adopting the dipole approximation. We illustrate the theory by time-dependent configuration interaction and coupled-cluster simulations of core-level absorption and circular dichroism spectra.
Cite
@article{arxiv.2307.02519,
title = {Transient spectroscopy from time-dependent electronic-structure theory without multipole expansions},
author = {Einar Aurbakken and Benedicte Sverdrup Ofstad and Håkon Emil Kristiansen and Øyvind Sigmundson Schøyen and Simen Kvaal and Lasse Kragh Sørensen and Roland Lindh and Thomas Bondo Pedersen},
journal= {arXiv preprint arXiv:2307.02519},
year = {2024}
}