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Photochemistry of SO sub 2 on Ag(111)

Journal Article · · Journal of Chemical Physics; (United States)
DOI:https://doi.org/10.1063/1.461575· OSTI ID:5200097
;  [1]
  1. Department of Chemistry and Biochemistry, University of Texas at Austin, Austin, Texas (USA)
The thermal and photon-induced chemistry of SO{sub 2} on Ag(111) has been studied using temperature programmed desorption (TPD), Auger electron spectroscopy (AES), and work function change ({Delta}{Phi}). SO{sub 2} adsorbs reversibly on Ag(111) and desorbs in peaks at 180 and 130 K for monolayer and multilayer, respectively. The work function increases to 0.33 eV upon saturation of the chemisorbed monolayer (ML), but drops to 0.20 eV for a physisorbed multilayer. UV photons (250--542 nm) induce desorption, but not decomposition, of chemisorbed SO{sub 2}. The photodesorption rate is first order in the photon flux, increases linearly with coverage up to 1 ML, but decreases sharply at higher coverages. For coverages up to 1 ML, the photodesorption cross section is (2.8{plus minus}0.2){times}10{sup {minus}20} cm{sup 2} at (313{plus minus}10) nm. The wavelength dependence is consistent with substrate, including bulk plasmon, excitation. Photodesorption mechanisms involving hot electron and hole attachment processes, only in the first monolayer, are discussed.
OSTI ID:
5200097
Journal Information:
Journal of Chemical Physics; (United States), Journal Name: Journal of Chemical Physics; (United States) Vol. 95:8; ISSN JCPSA; ISSN 0021-9606
Country of Publication:
United States
Language:
English