Resonant Photoionization of CO₂ up to the Fourth Ionization Threshold

Abstract

We present a comprehensive theoretical study of valence-shell photoionization of the CO 2 molecule by using the XCHEM methodology. This method makes use of a fully correlated molecular electronic continuum at a level comparable to that provided by state-of-the-art quantum chemistry packages in bound-state calculations. The calculated total and angularly resolved photoionization cross sections are presented and discussed, with particular emphasis on the series of autoionizing resonances that appear between the first and the fourth ionization thresholds. Ten series of Rydberg autoionizing states are identified, including some not previously reported in the literature, and their energy positions and widths are provided. This is relevant in the context of ongoing experimental and theoretical efforts aimed at observing in real-time (attosecond time scale) the autoionization dynamics in molecules.

Virtual Special Issue on Attosecond Chemistry

“…Along the same line, Ertel et al report a combined experimental and theoretical study showing the angular dependence of photoemission delays on methane and deuteromethane, and the effect of nuclear motion on such delays . The work of Pranjal et al reports a theoretical study of valence-shell photoionization of the triatomic molecule CO 2 . Here, the XCHEM methodology is used to describe the correlated electronic continuum, and several series of Rydberg autoionizing states have been identified, which are key to describing the autoionization dynamics occurring in the molecule.…”