INVESTIGADORES
GERONES Mariana
artículos
Título:
Evidence of Site-Specific Fragmentation on Thioacetic Acid, CH3C(O)SH, Irradiated with Synchrotron Radiation around the S 2p and O 1s Regions
Autor/es:
ERBEN, M. F; GERONES, M; ROMANO, R. M; DELLA VEDOVA, C. O
Revista:
JOURNAL OF PHYSICAL CHEMISTRY A
Editorial:
AMERICAN CHEMICAL SOCIETY
Referencias:
Lugar: WASHINGTON; Año: 2006 vol. 110 p. 875 - 883
ISSN:
1089-5639
Resumen:
Site-specific fragmentations following S 2p and O 1s photoexcitation of thioacetic acid, CH3C(O)SH,
have
been studied by means of synchrotron radiation. Total ion yield (TIY)
spectra were measured and
multicoincidence techniques, which include photoelectron-photoion
coincidence (PEPICO) and photoelectron-photoion-photoion coincidence
(PEPIPICO) time-of-flight mass spectrometry, were applied. The
equivalent-core approximation was employed in order to estimate
ionization transition values, and the observed peaks
were tentatively assigned. A site-specific fragmentation is moderately
observed by comparing the mass spectra
collected at resonant energies around the inner and shallow inner shell
S 2p and O 1s ionization edges.
Beside H+ ion, the most abundant ions observed at the S 2p edge excitation were CH3CO+, SH+, S+, and
CH3+. At the O 1s region the large CH3CO+ fragment was depressed, and small CHx+ (x = 0, 1, 2, 3), S+,
and SH+ fragments were dominant. The dissociation dynamic for the main ion-pair production has been
discussed. Two- and three-body dissociation channels have been observed in the PEPIPICO spectra, and the
dissociation mechanisms were proposed.