Photoexcitation, photoionization and photofragmentation studies on Pyrosulfuryl chloride, (ClSO2)2O, between 12 and 300 eV

MORENO BENTANCOURT, ANGÉLICA; ROMANO, ROSANA .M.; ERBEN, MAURICIO F.; CAVASSO FILHO, R. L.; GERONÉS, MARIANA; BERRUETA MARTINEZ, YANINA; RODRGÍGUEZ PIRANI, LUCAS S.; DELLA VÉDOVA, CARLOS OMAR

Campinas

Otro; 22ª RAU, Reunião Anual de Usuários do LNLS/CNPEM; 2012

Laboratório Nacional de Luz Síncrotron

Recent investigations in our research group have been dedicated to the elucidation of photochemical reaction mechanisms between small molecules, relevant as atmospheric contaminants or components. For example the photochemical gas-phase reaction between SO2, O2 and Cl2 was studied and the reaction mechanisms were proposed on the basis of the isolation and identification of the products.1 Molecules of the type ClSO2 (OSO2)nCl, with n=1,2 and the novel peroxide ClSO2OOSO2Cl were determined, among others, as the main photoproducts. It was proposed that this reaction could play an important role in atmospheric chemistry, particularly in regions of high Cl2 and SO2 abundances. It was also suggested that it could account for chemical processes to explain the unexpectedly low oxygen content of the Venus stratosphere.2 Pyrosulfuryl chloride, was prepared by the reaction of SO3 and CCl4,1 and subsequently purified by fractional distillation first, and then by trap-to-trap distillations in vacuum conditions. The identity and purity of the sample were checked by IR and Raman spectroscopy. The photoexcitation and photofragmentation in the energy region between 12 and 300 eV was studied. The Total Ion Yield (TIY) spectra show the S 2p, Cl 2p and S 2s edges, at 182.4, 212.4 and 236.6 eV, respectively. The most abundant ion detected in the PEPICO spectra, after the photoexcitation of the sample in the 12-21 eV energy region, was the ClSO2 + fragment (43.4% at 13 eV and 44.0% at 21 eV). At higher ionization energies, the atomization processes dominate the PEPICO spectra, being the abundances of O+, S+ and Cl+ 46.5, 15.9 and 22.2.