Positive and negative ion formation in deep-core excited molecules: S 1s excitation in dimethyl sulfoxide.
The photo-fragmentation of the dimethyl sulfoxide (DMSO) molecule was studied using synchrotron radiation and a magnetic mass spectrometer. The total cationic yield spectrum was recorded in the photon energy region around the sulfur K edge. The sulfur composition of the highest occupied molecular orbital's and lowest unoccupied molecular orbital's in the DMSO molecule has been obtained using both ab initio and density functional theory methods. Partial cation and anion-yield measurements were obtained in the same energy range. An intense resonance is observed at 2475.4 eV. Sulfur atomic ions present a richer structure around this resonant feature, as compared to other fragment ions. The yield curves are similar for most of the other ionic species, which we interpret as due to cascade Auger processes leading to multiply charged species which then undergo Coulomb explosion. The anions S(-), C(-), and O(-) are observed for the first time in deep-core-level excitation of DMSO.
Physics Institute, Federal University of Rio de Janeiro, Rio de Janeiro, RJ 21941-972, Brazil.
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LH
Coutinho
Department of Chemistry, University of Nevada, Las Vegas, Nevada 89154-4003, USA.
D J
DJ
Gardenghi
Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
A S
AS
Schlachter
Chemistry Institute, Federal University of Rio de Janeiro, Rio de Janeiro, RJ 21949-900, Brazil.
G G B
GG
de Souza
Department of Chemistry, University of Nevada, Las Vegas, Nevada 89154-4003, USA.
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WC
Stolte