Photoionization and Dissoziative Photoionization of Reactive Molecules Using Synchrotron Radiation

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In this project we will continue our research on the photoionization and dissociative photoionization of reactive molecules using synchrotron radiation. The molecules will be generated by pyrolysis from suitable precursors. Molecular parameters like ionization and appearance energies will be determined in order to derive thermochemical properties like binding energies and heats of formation. Furthermore the data will aid in the on-line identification of radicals in flames. A further exciting aspect of this project is the possibility to spectroscopically identify hitherto unknown reactive intermediates. We will extend our studies of reactive molecules containing heteroatoms, in particular nitrogen, because N-containing radicals are not well explored. We will investigate NH2 and NH, two small radicals of astrochemical relevance, the N-heterocyclic radicals pyridyl and pyrrolyl, which are expected to be present in biofuel combustion and the CNN radical. Another candidate is azaboridine, a heterocycle that contains B and N atoms. A further system of interest is the pyrolysis of diazomeldrums acid. Preliminary experiments indicate the formation of several unusual and not yet characterized species from this precursor, among them the linear chain NNCCO and an oxazole-ylidene. We will verify the generation of these species in further experiments. Studies on the photoionization of reactive hydrocarbons will be continued. Some of the less stable isomer of C7H6 have not yet been successfully characterized and will be readdressed. Subject of the next phase of the project are also the isomers of butenyl, C4H7. Finally we will determine the ionization energies of several polycyclic aromatic hydrocarbons (PAH) composed of five- and six-membered rings that are possibly involved in soot formation.