Low temperature surface photochemistry: O sub 2 and CO on Ag(110) at 30K

The photochemistry of O sub 2 adsorbed alone and of O sub 2 and CO coadsorbed on Ag(110) at 30K was investigated with temperature programmed desorption (TPD), electron energy loss spectroscopy (EELS), and mass spectroscopy performed during sample irradiation. O sub 2 was found to desorb following ph...

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Bibliographic Details
Published in:Surface science 1994-12, Vol.321 (3), p.L233-L238
Main Authors: Pelak, R A, Ho, W
Format: Article
Language:English
Online Access:Get full text
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Summary:The photochemistry of O sub 2 adsorbed alone and of O sub 2 and CO coadsorbed on Ag(110) at 30K was investigated with temperature programmed desorption (TPD), electron energy loss spectroscopy (EELS), and mass spectroscopy performed during sample irradiation. O sub 2 was found to desorb following photoconversion to the chemically adsorbed state for lambda < =436 nm, as well as directly from the physically adsorbed state for lambda < =600 nm. From the coadsorbed system, CO sub 2 photoproduction occurs over the same wavelength range as O sub 2 photodesorption ( lambda < =600 nm), while CO photodesorption is observed for lambda < =500 nm. The observed wavelength dependences are found to be consistent with a photoexcitation mechanism involving the attachment of an excited substrate electron to the physically adsorbed O sub 2 molecule. CO sub 2 photoproduction is believed to occur via reactions between adsorbed CO molecules and both ``hot'' O atoms and chemically adsorbed O sub 2 molecules. Copyright (c) 1995 Elsevier Science B.V. All rights reserved.
ISSN:0039-6028