Photoexcitation, Photoionization, and Photofragmentantion of CF₃CF₂CF₂C(O)Cl Using Synchrotron Radiation between 13 and 720 eV

Abstract

The main inner shell ionization edges of gaseous CF3CF2CF2C(O)Cl, including Cl 2p, C 1s, O 1s, and F 1s, have been measured in Total Ion Yield (TIY) mode by using tunable synchrotron radiation, and several resonance transitions have been assigned with the help of quantum chemical calculations. Interestingly, resonance transitions observed in the C 1s region can be assigned to different carbon atoms in the molecule according to the degree of fluorine substitution. Ionic photofragmentation processes have been studied by time-of-flight mass spectrometry in the Photoelectron-Photoion-Coincidence (PEPICO) and Photoelectron-Photoion-Photoion-Coincidence (PEPIPICO) modes. These techniques revealed a "memory-lost" effect especially around the C 1s region, since the fragmentation events are independent of the energy range considered. Moreover, different fragmentation mechanisms were inferred from these spectra in the valence (13.0-21.0 eV) as well as in the inner (180.0-750.0 eV) electronic energy regions. The vibrational spectral features of CF3CF2CF2C(O)Cl have been interpreted in terms of a conformational equilibrium between two conformations (gauche and anti of the CC single bond with respect to the CCl one) at room temperature, as determined from quantum chemical calculations and the detailed analysis of the infrared spectrum.

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

“…The signal located at 531.7 eV is straightforwardly associated with an O 1s to π*­(CO) transition . Moreover, the O 1s ionization potential is around 539 eV, similar to that in trifluoroacetic acid .…”

“…The experimental set-up has been previously described elsewhere. 23 Perfluoropropionic acid 97 % was purchased from Sigma Aldrich and used as received.…”

“…233 The region of 695 eV, typical of a number of F 1s → σ *(C−F) resonance electronic transitions, appears congested, but its shape, determined by the proximity of several transitions, resembles that observed for other, related fluorine-containing molecules. 23 The F 1s ionization potential appears at 697.7 eV in PFPA (Figure 2).…”

Electronic properties and photofragmentation mechanisms of pyrosulfuryl chloride, ClSO2OSO2Cl

“…The study presented here is part of a general project aimed to photochemical studies of species with atmospheric interest, as for example fluorinated alcohols (CF3CH2OH) [5], perfluorocarbons (CF3CF2CF2C(O)Cl) [6], compounds containing the SO2 group (FSO2NCO [7], ClSO2NCO) [8], among others. The main objective of these studies is the determination of the photochemical mechanisms through the detection of the photoproducts and reactive intermediates, allowing the modeling of possible atmospheric process.…”

“…Below the first ionization potential, in the region of visible and UV light, the fragmentation process occurring through free radicals and producing neutral species are followed mainly by IR spectroscopy [9,10]. When ionizing radiation is used, in the VUV and X ray region, electron and ionic species are detected [5][6][7][8].…”