Optically enhanced electron attachment to thiophenol

Journal Article · Thu Jun 01 04:00:00 EDT 1989 · J. Chem. Phys.; (United States)

DOI:https://doi.org/10.1063/1.456344· OSTI ID:6083445

Pinnaduwage, L A; Christophorou, L G; Hunter, S R

Enhanced electron attachment to KrF excimer laser irradiated thiophenol (C/sub 6/H/sub 5/SH) molecules has been studied in a electron swarm experiment using nitrogen as the buffer gas. Two distinct electron attachment processes were found to be responsible for the observed large enhancement in electron attachment under different experimental conditions. One enhanced electron attachment process occurred immediately (within a few ..mu..s) after laser irradiation and is shown to be due to dissociative electron attachment to electronically excited thiophenol molecules in their first excited triplet state produced indirectly via excited singlet states reached by excimer laser irradiation. At low mean electron energies (/similar to/0.1 eV), up to 5 orders of magnitude enhancement in electron attachment has been observed for the triplet state compared to the ground electronic state. This enhanced electron attachment decreased with (i) increasing nitrogen pressure due to quenching of the first excited singlet state of thiophenol (precursor of the triplet state) by nitrogen, and (ii) increasing time delay between laser irradiation and subsequent electron attachment to the laser-irradiated molecules. This latter observation is shown to be due to the self-(triplet--triplet) quenching of the electron attaching triplet state molecules. The second observed enhanced electron attachment process occurred at longer times (>100 ..mu..s) after laser irradiation and is attributed to the electron attachment to diphenyl disulfide (C/sub 6/H/sub 5/SSC/sub 6/H/sub 5/) produced by the interaction of thiophenoxy radicals (C/sub 6/H/sub 5/Sts-dot) formed directly or indirectly via laser irradiation.

• Research Organization: Atomic, Molecular, and High Voltage Physics Group, Health and Safety Research Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831
• DOE Contract Number: AC05-84OR21400
• OSTI ID: 6083445
• Journal Information: J. Chem. Phys.; (United States), Journal Name: J. Chem. Phys.; (United States) Vol. 90:11; ISSN JCPSA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201 -- Chemical & Physicochemical Properties
400500* -- Photochemistry
AROMATICS
CHEMICAL REACTIONS
DE-EXCITATION
DISSOCIATION
ELECTROMAGNETIC RADIATION
ELECTRON ATTACHMENT
ENERGY LEVELS
ENERGY RANGE
ENERGY TRANSFER
ENERGY-LEVEL TRANSITIONS
EV RANGE
EV RANGE 01-10
EXCITED STATES
HYDROXY COMPOUNDS
IONIZATION
LASER RADIATION
ORGANIC COMPOUNDS
ORGANIC SULFUR COMPOUNDS
PHENOLS
PHOTOCHEMICAL REACTIONS
PHOTOIONIZATION
QUENCHING
RADIATIONLESS DECAY
RADIATIONS