Photoionization cross sections for reaction intermediates in hydrocarbon combustion

Previously unmeasured absolute photoionization cross sections are presented for eight common reaction intermediates found in the combustion of many simple hydrocarbons. Total photoionization cross sections recorded for 11 additional hydrocarbons are in good agreement with previous studies. The measurements are performed with photoionization mass spectrometry (PIMS), using VUV synchrotron radiation. Absolute cross sections for molecular and dissociative photoionization are determined by comparison of the photoionization efficiencies for each intermediate with that of propene, used as a calibration standard, for photon energies from 9.7 to 11.75 eV, recorded with a photon energy resolution of 50 meV(fwhm).