Multielectron dynamics, polarization, and Stark shifts for carbon monoxide molecule and molecular ions in a strong laser field

Abstract

The ionization of CO, CO+, and CO2+ are quantified in an ultrafast, strong laser field. Measurements were performed over the intensity range from 1014 to 1017 W cm−2. Across this span, the intensity-dependent ionization yields were quantified over eight orders of magnitude in the dynamic range. Both sequential and (e, 2e) nonsequential ionization processes were observed. We calculate the electron states for CO and its molecular ions interacting with a strong laser field using a traditional field-free approach, the single active electron approximation, and present the results for the all-electron interaction of CO with the laser field. By comparing the calculated ionization with the experimental yields, we determined that the electron wave function polarization and Stark shifts were accurately treated with an all-electron Hartree–Fock calculation. The calculated field–molecule interaction included the core electron polarizability, which is not captured using field-free or frozen-core single-electron approximation.