Dissociative Photoionization of ClC(O)SCH3 induced by synchrotron radiation

M. GERONÉS; M. F. ERBEN; R. M. ROMANO; C. O. DELLA VÉDOVA

Rio de Janeiro, Brazil

Simposio; International Symposium Scattering, Coincidence and Absorption Studies of Molecules (SCASM); 2006

Laboratório Nacional de Luz Síncrotron

Ionization and fragmentation of ClC(O)SCH3 after photoexcitation around the S 2p and Cl 2p edges, have been studied by using the TGM beam line available at the LNLS (Campinas). This study is part of a more general project aimed to the study of XC(O)SY compound, such as FC(O)SCl [1], ClC(O)SCl [2], CH3C(O)SH. Results include the measurement of the Total Ion Yield spectrum and the PEPICO and PEPIPICO spectra below, on, and above each ionization edge. In the course of the analysis of the PEPICO spectra, the possible presence of site-specific fragmentation can be analyzed. PEPIPICO spectra allow us to deduce the dissociation mechanisms originated by electron excitation. The TOF mass spectra show peaks corresponding to the following ions: H+, CHx+ (x = 0, 1, 2, 3), O+ or S2+, CO+, S+, Cl+, CS+, SCH3+, OCS+, ClCO+, C(O)SCH3+. The parent molecular ion can be observed and shows the characteristic chlorine isotopic distribution. Some of the most important double coincidences are: C(O)SCH3+/Cl+, ClCO+/SCH3+, CO+/CH3+, Cl+/CH3+. The first two can be described by simple two-body fragmentations. References: [1] M. F. Erben, R. M. Romano, and C. O. Della Védova, J. Phys. Chem. A. 108, 3938 (2004). [2] M. F. Erben, R. M. Romano, and C. O. Della Védova, J. Phys. Chem. A. 109, 304 (2005). Acknowledgements: This work was supported by LNLS, UNLP, CONICET, CIC, and Fundación Antorchas.