Estimate of the C-Cl Photoionization Cross Section and Absolute Photoionization Cross Sections of Chlorinated Organic Compounds.

Chlorinated organic compounds are prominently used for industrial production, but their vapors and emission byproducts can cause detrimental effects to human health and the environment. To accurately quantify organochlorine compounds, the absolute photoionization cross section of tetrachloroethylene, chlorobenzene, 1,2-dichlorobenzene, and chloroacetone are measured using multiplexed synchrotron photoionization mass spectrometry at the Advanced Light Source at Lawrence Berkeley National Laboratory. These measurements allow for the estimation of the C-Cl photoionization cross section, increasing quantification accuracy of chlorinated emissions for kinetic modeling and pollutant mitigation. CBS-QB3 calculations of adiabatic ionization energies and thermochemical appearance energies are also presented and agree well with the experimental results. The ion signals from chlorinated isotopologues are summated to estimate the average photoionization cross section of the carbon-chlorine bond. This estimation allows for further gas-phase quantification of organochlorine molecules that do not have photoionization cross section references. image