Photofragmentation Mechanisms of Chlorosulfonyl Isocyanate, ClSO2NCO, Excited with Synchrotron Radiation between 12 and 550 eV

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• 作者：Ang茅lica Moreno Betancourt ; Yanina B. Bava ; Yanina Berrueta Mart铆nez ; Mauricio F. Erben ; Reinaldo L. Cavasso Filho ; Carlos O. Della V茅dova ; Rosana M. Romano
• 刊名：Journal of Physical Chemistry A
• 出版年：2015
• 出版时间：July 23, 2015
• 年：2015
• 卷：119
• 期：29
• 页码：8021-8030
• 全文大小：641K
• ISSN：1520-5215

文摘

The unimolecular photofragmentation mechanisms of chlorosulfonyl isocyanate, ClSO₂NCO, excited with tunable synchrotron radiation between 12 and 550 eV, were investigated by means of time-of-flight (TOF) coincidence techniques. The main fragmentation mechanism after single ionization, produced by irradiation of an effusive beam of the sample with synchrotron light in the valence electron region, occurs through the breaking of the Cl鈥揝 single bond, giving a chloride radical and a SO₂NCO⁺ fragment. This mechanism contrasts with the one observed for the related FSO₂NCO, in which the rupture of the S鈥揘 bond originates the FSO₂⁺ fragment. The energies of the shallow- (S 2p, Cl 2p, and S 2s) and core-shell (C 1s, N 1s, and O 1s) electrons were determined by X-ray absorption. Transitions between these shallow and core electrons to unoccupied molecular orbitals were also observed in the total ion yield (TIY) spectra. Fourteen different fragmentation mechanisms of the doubly charged parent ion, ClSO₂NCO²⁺, were inferred from the bidimensional photoelectron-photoion-photoion-coincidence (PEPIPICO) spectra. The rupture of the S鈥揘 bond can evolve to form NCO⁺/SO₂^鈥?, NCO⁺/SO^鈥?, or S^鈥?/NCO⁺ pairs of ions. The Cl鈥揝 bond breaking originates different mechanisms, Cl⁺/SO^鈥?, Cl⁺/S^鈥?, CO^鈥?/S^鈥?, O^鈥?/SO^鈥?, O^鈥?/Cl⁺, O^鈥?/S^鈥?, C^鈥?/S^鈥?, and C^鈥?/O^鈥? pairs being detected in coincidence as the final species. Another three coincidence islands can only be explained with an initial atomic rearrangement forming ClNCO²⁺, ONCO²⁺, and ClCO²⁺, as precursors of CO^鈥?/Cl⁺, O^鈥?/CO^鈥?, and C^鈥?/Cl⁺ pairs, respectively. The formation of Cl^{鈥?/sup> radical is deduced from several mechanisms.}