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Title: Mechanisms for the near-UV photodissociation of CH{sub 3}I on D{sub 2}O/Cu(110)

Abstract

The system of CH{sub 3}I adsorbed on submonolayer, monolayer, and multilayer thin films of D{sub 2}O on Cu(110) has been studied by measuring the time of flight (TOF) distributions of the desorbing CH{sub 3} fragments after photodissociation using linearly polarized {lambda} = 248 nm light. For multilayer D{sub 2}O films (2-120 ML), the photodissociation is dominated by neutral photodissociation via the 'A-band' absorption of CH{sub 3}I. The polarization and angle dependent variation in the observed TOF spectra of the CH{sub 3} photofragments find that dissociation is largely via the {sup 3}Q{sub 0} excited state, but that also a contribution via the {sup 1}Q{sub 1} excitation can be identified. The photodissociation results also indicate that the CH{sub 3}I adsorbed on D{sub 2}O forms close-packed islands at submonolayer coverages, with a mixture of C-I bond axis orientations. For monolayer and submonolayer quantities of D{sub 2}O we have observed a contribution to CH{sub 3}I photodissociation via dissociative electron attachment (DEA) by photoelectrons. The observed DEA is consistent with delocalized photoelectrons from the substrate causing the observed dissociation- we do not find evidence for an enhanced DEA mechanism via the temporary solvation of photoelectrons in localized states of the D{sub 2}O ice.

Authors:
; ;  [1]
  1. Physics Department, University of Northern British Columbia, 3333 University Way, Prince George, British Columbia V2N 4Z9 (Canada)
Publication Date:
OSTI Identifier:
22105391
Resource Type:
Journal Article
Journal Name:
Journal of Chemical Physics
Additional Journal Information:
Journal Volume: 138; Journal Issue: 8; Other Information: (c) 2013 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; 74 ATOMIC AND MOLECULAR PHYSICS; ABSORPTION; ADSORPTION; COPPER; DISSOCIATION; ELECTRON ATTACHMENT; EXCITATION; EXCITED STATES; HEAVY WATER; LAYERS; METHYL IODIDE; PHOTOLYSIS; SUBSTRATES; THIN FILMS; TIME-OF-FLIGHT METHOD

Citation Formats

Miller, E. R., Muirhead, G. D., and Jensen, E. T. Mechanisms for the near-UV photodissociation of CH{sub 3}I on D{sub 2}O/Cu(110). United States: N. p., 2013. Web. doi:10.1063/1.4770225.
Miller, E. R., Muirhead, G. D., & Jensen, E. T. Mechanisms for the near-UV photodissociation of CH{sub 3}I on D{sub 2}O/Cu(110). United States. https://doi.org/10.1063/1.4770225
Miller, E. R., Muirhead, G. D., and Jensen, E. T. 2013. "Mechanisms for the near-UV photodissociation of CH{sub 3}I on D{sub 2}O/Cu(110)". United States. https://doi.org/10.1063/1.4770225.
@article{osti_22105391,
title = {Mechanisms for the near-UV photodissociation of CH{sub 3}I on D{sub 2}O/Cu(110)},
author = {Miller, E. R. and Muirhead, G. D. and Jensen, E. T.},
abstractNote = {The system of CH{sub 3}I adsorbed on submonolayer, monolayer, and multilayer thin films of D{sub 2}O on Cu(110) has been studied by measuring the time of flight (TOF) distributions of the desorbing CH{sub 3} fragments after photodissociation using linearly polarized {lambda} = 248 nm light. For multilayer D{sub 2}O films (2-120 ML), the photodissociation is dominated by neutral photodissociation via the 'A-band' absorption of CH{sub 3}I. The polarization and angle dependent variation in the observed TOF spectra of the CH{sub 3} photofragments find that dissociation is largely via the {sup 3}Q{sub 0} excited state, but that also a contribution via the {sup 1}Q{sub 1} excitation can be identified. The photodissociation results also indicate that the CH{sub 3}I adsorbed on D{sub 2}O forms close-packed islands at submonolayer coverages, with a mixture of C-I bond axis orientations. For monolayer and submonolayer quantities of D{sub 2}O we have observed a contribution to CH{sub 3}I photodissociation via dissociative electron attachment (DEA) by photoelectrons. The observed DEA is consistent with delocalized photoelectrons from the substrate causing the observed dissociation- we do not find evidence for an enhanced DEA mechanism via the temporary solvation of photoelectrons in localized states of the D{sub 2}O ice.},
doi = {10.1063/1.4770225},
url = {https://www.osti.gov/biblio/22105391}, journal = {Journal of Chemical Physics},
issn = {0021-9606},
number = 8,
volume = 138,
place = {United States},
year = {Thu Feb 28 00:00:00 EST 2013},
month = {Thu Feb 28 00:00:00 EST 2013}
}