HeI Photoelectron and Valence Synchrotron Photoionization Studies of the Thioester Molecule CH3C(O)SCH3: Evidence of Vibronic Structure

GERONES, M; DOWNS, A.J; ERBEN, M. F; GE, M; ROMANO, R. M; YAO, L; DELLA VEDOVA, C. O

JOURNAL OF PHYSICAL CHEMISTRY A

AMERICAN CHEMICAL SOCIETY

Lugar: WASHINGTON; Año: 2008 vol. 112 p. 5947 - 5953

1089-5639

One of the simplest thioester molecules, S-methyl thioacetate, CH3C(O)SCH3, has been investigated by HeI photoelectron spectroscopy (PES) and valence photoionization studies using synchrotron radiation in the same energy range. In the second series of experiments, total ion yield (TIY), photoelectron photoion coincidence (PEPICO), and partial ion yield (PIY) spectra were recorded. It was found that the photodissociation behavior of CH3C(O)SCH3 can be divided into three well-defined energy regions. Vibronic structure was observed in the valence synchrotron photoionization process, being associated with wavenumbers of 912, 671, 1288, 1690, and 1409 cm-1 for the bands at 12.82, 13.27, 15.66, 15.72, and 17.42 eV, respectively. Evaluation of the PE spectrum in concert with the synchrotron photoionization measurements and complemented by highlevel ab initio calculations thus provides unusually detailed insights into the valence ionization processes of this molecule.