Valence and Inner Electronic Excitation, Ionization and Fragmentation of Perfluoropropionic Acid.

The photoexcitation, photoionization and photofragmentation of gaseous CF3CF2C(O)OH were studied by means of synchrotron radiation in the valence and inner energy regions. Photofragmentation events were detected from 11.7 eV through formation of COH+, C2F4+ and the parent species M+. Since the vertical ionization potential has been reported at 11.94 eV, the starting energy used in this study, 11.7 eV, falls just inside the tale of the ionization band in the photoelectron spectra. Together, therefore, with the foremost ionization process, autoionization or adiabatic ionization cannot be discounted in order to explain the observed production of ions. The information from the Total Ion Yield spectra around the C 1s, O 1s and F 1s ionization potentials allows the energies at which different resonance transitions take place in the molecule to be determined. These transitions have been assigned by comparison with the results of the analysis of similar compounds. In the inner energy region both kinetic energy release (KER) values and the slope and shape of double coincidence islands obtained from PhotoElectron-PhotoIon-PhotoIon-Coincidence (PEPIPICO) spectra allow different photofragmentation mechanisms to be elucidated.