Potentials, exchange, and correlation in attosecond photoemission delays

Abstract

We investigate attosecond time delays in the emission of photoelectrons using a hierarchy of models of the $C{O}_2$ 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.