Photoionization detection of CF_2 radicals resulting from the IR multiple-photon dissociation of CF_2HCl molecules in a molecular beam

摘要

CF~+ ions were detected when irradiating the CF_2 radicals resulting from the IR multiple-photon dissociation (MPD) of jet-cooled CF_2HCl molecules with an intense pulsed UV radiation (λ ≤ 244 nm). The experiments performed allowed us to conclude that the CF~+ ions observed were produced in the UV multiphoton excitation of the CF_2 radicals via the resonant intermediate state (A-tilde)~1B_1, followed by their fragmentation and ionization. This effect was used to study the unimolecular decay of CF_2HCl under molecular beam conditions. We measured the kinetics of this process, as well as the translational energies of the CF_2 radicals. The isotopic selectivity of the IR MPD of ~(13)CF_2HCl was found to improve substantially under jet-cooled molecular beam conditions.