Multielectron effects in strong field ionization of CO$_2$: impact on differential photoelectron spectra

Abstract

We report fully differential photoelectron spectra from an {\it ab-inito} coupled channels treatment of CO$_2$. Photoionization by laser pulses centered at 400 nm and 800 nm wavelength are considered, with arbitrary molecular alignment and polarization (linear and elliptic). Calculations reveal significant excited state channel contributions that are, at certain molecular orientations, an order of magnitude larger than the ground state channel in the rescattering plateau. Partial wash out of the multiphoton structure in the ATI spectra and of the nodal features in angle resolved spectra is observed due to ionization to excited state channels. The qualitative nature of the spectra is determined by ionization thresholds, orbital symmetries and interchannel coupling in the order of precedence.