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Title: Electron stimulated desorption of anionic fragments from films of pure and electron-irradiated thiophene

Abstract

The electron stimulated desorption (ESD) of anions is used to explore the effects of electron irradiation on a thiophene film and we report measurements for electron impact on multilayer thiophene condensed on a polycrystalline platinum substrate. Below 22 eV and at low electron dose, desorbed anions include H{sup -} (the dominant signal) as well as S{sup -}, CH{sub 2}{sup -}, SH{sup -} and SCH{sub 2}{sup -}. Yield functions show that anions are desorbed both by dissociative electron attachment (DEA) with resonances observed at 9.5, 11, and 16 eV, and for energies >13 eV, by dipolar dissociation (DD). An increase in the S{sup -} signal from electron irradiated (beam-damaged) thiophene films and the appearance of a new DEA resonance in the S{sup -} yield function at 6 eV are linked to rupture of the thiophene ring and the formation of sulfur-terminated products within the film. The threshold energy for ring rupture is 5 eV. The desorption of new anions such as C{sub 4}H{sub 3}S{sup -} (Thiophene-H){sup -}is also observed from electron irradiated films and these likely arise from the decomposition of large radiation product molecules synthesized in the film. The yield functions of H{sup -}, S{sup -}, SH{sup -}, (Thiophene-H){sup -},more » and (Thiophene+H){sup -} anions from irradiated thiophene films that have been annealed to 300 K, each exhibit a single resonant feature centered around 5.1 eV, suggesting that all signals derive from DEA to the same molecular radiation product. In contrast, only H{sup -} and S{sup -} are observed to desorb from films of 2-2-bithiophene and no resonance is seen below {approx}10 eV in the anion yield functions. These data suggest that electron irradiation causes formation of ring-opened oligomers, and that closed-ring or 'classical' oligomers, (similar to bithiophene) if formed, contribute little to the ESD of anions.« less

Authors:
; ; ; ;  [1]
  1. Department of Physics and Astronomy and Laboratory for Surface Modification, Rutgers, State University of New Jersey, Piscataway, New Jersey 08854 -8019 (United States)
Publication Date:
OSTI Identifier:
20864290
Resource Type:
Journal Article
Journal Name:
Journal of Chemical Physics
Additional Journal Information:
Journal Volume: 125; Journal Issue: 9; Other Information: DOI: 10.1063/1.2338030; (c) 2006 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0021-9606
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; 36 MATERIALS SCIENCE; ANNEALING; DECOMPOSITION; DESORPTION; DISSOCIATION; ELECTRON ATTACHMENT; ELECTRON BEAMS; ELECTRONS; EV RANGE 01-10; EV RANGE 10-100; HYDROGEN IONS 1 MINUS; IRRADIATION; PLATINUM; POLYCRYSTALS; SULFUR IONS; TEMPERATURE RANGE 0273-0400 K; THIN FILMS; THIOPHENE

Citation Formats

Hedhili, M N, Cloutier, P, Bass, A D, Madey, T E, Sanche, L, Groupe en Sciences des Radiations, Faculte de Medecine, Universite de Sherbrooke, Sherbrooke, Quebec J1H 5N4, Department of Physics and Astronomy and Laboratory for Surface Modification, Rutgers, The State University of New Jersey, Piscataway, New Jersey 08854 -8019, and Groupe en Sciences des Radiations, Faculte de Medecine, Universite de Sherbrooke, Sherbrooke, Quebec J1H 5N4. Electron stimulated desorption of anionic fragments from films of pure and electron-irradiated thiophene. United States: N. p., 2006. Web. doi:10.1063/1.2338030.
Hedhili, M N, Cloutier, P, Bass, A D, Madey, T E, Sanche, L, Groupe en Sciences des Radiations, Faculte de Medecine, Universite de Sherbrooke, Sherbrooke, Quebec J1H 5N4, Department of Physics and Astronomy and Laboratory for Surface Modification, Rutgers, The State University of New Jersey, Piscataway, New Jersey 08854 -8019, & Groupe en Sciences des Radiations, Faculte de Medecine, Universite de Sherbrooke, Sherbrooke, Quebec J1H 5N4. Electron stimulated desorption of anionic fragments from films of pure and electron-irradiated thiophene. United States. https://doi.org/10.1063/1.2338030
Hedhili, M N, Cloutier, P, Bass, A D, Madey, T E, Sanche, L, Groupe en Sciences des Radiations, Faculte de Medecine, Universite de Sherbrooke, Sherbrooke, Quebec J1H 5N4, Department of Physics and Astronomy and Laboratory for Surface Modification, Rutgers, The State University of New Jersey, Piscataway, New Jersey 08854 -8019, and Groupe en Sciences des Radiations, Faculte de Medecine, Universite de Sherbrooke, Sherbrooke, Quebec J1H 5N4. Thu . "Electron stimulated desorption of anionic fragments from films of pure and electron-irradiated thiophene". United States. https://doi.org/10.1063/1.2338030.
@article{osti_20864290,
title = {Electron stimulated desorption of anionic fragments from films of pure and electron-irradiated thiophene},
author = {Hedhili, M N and Cloutier, P and Bass, A D and Madey, T E and Sanche, L and Groupe en Sciences des Radiations, Faculte de Medecine, Universite de Sherbrooke, Sherbrooke, Quebec J1H 5N4 and Department of Physics and Astronomy and Laboratory for Surface Modification, Rutgers, The State University of New Jersey, Piscataway, New Jersey 08854 -8019 and Groupe en Sciences des Radiations, Faculte de Medecine, Universite de Sherbrooke, Sherbrooke, Quebec J1H 5N4},
abstractNote = {The electron stimulated desorption (ESD) of anions is used to explore the effects of electron irradiation on a thiophene film and we report measurements for electron impact on multilayer thiophene condensed on a polycrystalline platinum substrate. Below 22 eV and at low electron dose, desorbed anions include H{sup -} (the dominant signal) as well as S{sup -}, CH{sub 2}{sup -}, SH{sup -} and SCH{sub 2}{sup -}. Yield functions show that anions are desorbed both by dissociative electron attachment (DEA) with resonances observed at 9.5, 11, and 16 eV, and for energies >13 eV, by dipolar dissociation (DD). An increase in the S{sup -} signal from electron irradiated (beam-damaged) thiophene films and the appearance of a new DEA resonance in the S{sup -} yield function at 6 eV are linked to rupture of the thiophene ring and the formation of sulfur-terminated products within the film. The threshold energy for ring rupture is 5 eV. The desorption of new anions such as C{sub 4}H{sub 3}S{sup -} (Thiophene-H){sup -}is also observed from electron irradiated films and these likely arise from the decomposition of large radiation product molecules synthesized in the film. The yield functions of H{sup -}, S{sup -}, SH{sup -}, (Thiophene-H){sup -}, and (Thiophene+H){sup -} anions from irradiated thiophene films that have been annealed to 300 K, each exhibit a single resonant feature centered around 5.1 eV, suggesting that all signals derive from DEA to the same molecular radiation product. In contrast, only H{sup -} and S{sup -} are observed to desorb from films of 2-2-bithiophene and no resonance is seen below {approx}10 eV in the anion yield functions. These data suggest that electron irradiation causes formation of ring-opened oligomers, and that closed-ring or 'classical' oligomers, (similar to bithiophene) if formed, contribute little to the ESD of anions.},
doi = {10.1063/1.2338030},
url = {https://www.osti.gov/biblio/20864290}, journal = {Journal of Chemical Physics},
issn = {0021-9606},
number = 9,
volume = 125,
place = {United States},
year = {2006},
month = {9}
}