VUV-Induced Photodissociation of the Chloroacetone Molecule Studied by Photoelectron-Photoion Coincidence Spectroscopy

The dissociative photoionization dynamics of the chloroacetone molecule (C3H5OCl) in the gas phase, induced by vacuum ultraviolet (VUV) synchrotron radiation in the range from 10.85 to 21.50 eV, has been investigated by using time-of-flight mass spectrometry in the photoelectron-photoion coincidence mode. The appearance energies for the most relevant cation fragments produced in this energy range have been analyzed, and the fragmentation pathways leading to the formation of the cation species have been proposed and discussed. The mass spectra show that the most dominant VUV photodissociation cation product appears at m/z 43 and has been assigned to the C2H3O+ species. Enthalpies of formation (Delta H-f(0K)degrees) for the neutral chloroacetone molecule and its molecular cation have been derived and correspond to -207.8 +/- 5.8 kJ/mol and 755.1 +/- 6.8 kJ/mol, respectively. In addition to the spectral analysis, the structural and energetic parameters for the cations produced have also been examined on the basis of high-level quantum chemical numerical calculations.

Automated summary

The dissociative photoionization dynamics of the chloroacetone molecule in the gas phase induced by VUV synchrotron radiation has been investigated. The appearance energies for relevant cation fragments, fragmentation pathways, and cation species have been analyzed and discussed. In addition, structural and energetic parameters of the cations were examined based on quantum chemical numerical calculations.