Interstellar H3+ and HCS+ Ions produced in the Dissociative Photoionization Process of CH3C(O)SCH3 in the Proximity of the Sulfur 2p, Carbon 1s and O 1s Edges

GERONÉS, MARIANA; ERBEN, MAURICIO FEDERICO; ROMANO, ROSANA MARIEL; CAVASSO FILHO, REINALDO; DELLA VÉDOVA, CARLOS OMAR

JOURNAL OF PHYSICAL CHEMISTRY A

AMER CHEMICAL SOC

Lugar: Washington; Año: 2012 vol. 116 p. 2571 - 2582

1089-5639

In this work we present a study of the dissociative photoionization of S-methyl thioacetate [CH3C(O)SCH3] by using multicoincidence time-of-flight mass spectrometry and synchrotron radiation in the S 2p, C 1s, and O 1s edges. Total and partial ion yield spectra together with photoelectron−photoion coincidence (PEPICO) and photoelectron−photoion−photoion coincidence (PEPIPICO) spectra were measured. Fragmentation patterns deduced from PEPICO and PEPIPICO spectra at the various excitation energies show a moderate site-specific fragmentation. The dissociation dynamic for the main ion-pair production is discussed. Two-, three-, and four-body dissociation channels have been observed in the PEPIPICO spectra, and the dissociation mechanisms are proposed. The interstellar HCS+ and H3+ ions can be observed during the synchrotron experiments reported in the present work.