Unimolecular dissociation rates of the chlorobenzene cation prepared by multiphoton ionization

Publisher Website
Google Scholar
Abstract
We have studied the unimolecular reaction C6H5Cl+→C6H+5 +Cl as a function of internal energy by using multiphoton ionization (MPI) on a supersonically cooled jet of chlorobenzene to prepare the excited parent ion. Specific rate constants k(E) were obtained from an analysis of the distorted C6H+5 peak shape in a time‐of‐flight (TOF) mass spectrometer. Decomposition in the wavelength region 265–270 nm is shown to proceed by two‐photon ionization followed by one‐photon absorption. The internal energy of the excited parent ion is characterized in a separate experiment which measures the photoelectron kinetic energy distribution, obtained over the same wavelength range. The specific rate constants found in this study compare well with previous literature values, thus validating this MPI TOF technique for the determination of ion decomposition rates.