Electron-Ion Interaction Effects in Attosecond Time-Resolved Photoelectron Spectra

Photoionization by attosecond (as) extreme ultraviolet (xuv) pulses into the laser-dressed continuum of the ionized atom is commonly described in strong-field approximation (SFA), neglecting the Coulomb interaction between the emitted photoelectron (PE) and residual ion. By solving the time-dependent Sch\"{o}dinger equation (TDSE), we identify a temporal shift $\delta \tau$ in streaked PE spectra, which becomes significant at small PE energies. Within an eikonal approximation, we trace this shift to the combined action of Coulomb and laser forces on the released PE, suggesting the experimental and theoretical scrutiny of their coupling in streaked PE spectra. The initial state polarization effect by the laser pulse on the xuv streaked spectrum is also examined.