Potentials, exchange, and correlation in attosecond photoemission delays

TL;DR

This paper explores how various theoretical models, including ab initio methods, affect the understanding of attosecond photoemission delays in CO2, highlighting the significant impact of electron exchange and correlation.

Contribution

It introduces an ab initio quantum-chemical approach that fully incorporates multi-electron exchange and correlation effects in attosecond photoemission delay calculations.

Findings

Exchange and correlation significantly influence delay times.

Different models modify delays by 10 attoseconds or more.

Multi-electron effects are crucial for accurate predictions.

Abstract

We investigate attosecond time delays in the emission of photoelectrons using a hierarchy of models of the $CO_2$ molecule including the strong field approximation, Coulomb-scattering, short-range parts of the molecular potential, Hartree and Hartree-Fock descriptions. In addition, we present an {\it ab initio} calculation based on quantum-chemical structure in combination with strong-field techniques, which fully includes multi-electron exchange and correlation. Every single of these model constituents is found to modify delays on the scale of 10 as or more, with exchange and correlation having the most pronounced effect.