Abstract

We investigate strong-field XUV-IR pump-probe dissociative ionization of CO₂ by solving the Schrödinger equation for the nuclear motion in full dimensionality on the lowest five coupled Oppenheimer (BO) potential-energy surfaces. Applying a multi-configurational self-consistent-field quantum-chemistry code to calculate ab initio non-BO, laser dipole, and spin-orbit couplings between adiabatic electronic states, we provide kinetic energy release (KER) spectra for the O(3P_g) + CO⁺( X²Σ⁺) and O⁺(⁴S_u) + CO(X¹Σ₊) dissociation channels and their branching ratio. Our KER spectra identify the vibrational excitations of CO⁺ fragments along a dominant 3ω dissociation paths. Mediated by the nuclear dynamics near the conical intersection of the CO₂⁺ A²∏_u and B²Σ_u⁺ states, we reproduce a core-hole oscillation period 115 fs, in good agreement with the experiment of Timmers et al. [1]. In addition, we find 62 fs oscil-lations in the CO⁺ fragmentation channel due to quantum beats between specific vibrational and electronic CO₂⁺ states.

© 2023 The Author(s)