AVS 51st International Symposium
    Surface Science Wednesday Sessions
       Session SS1-WeM

Paper SS1-WeM4
Thermodynamics of Pd(111) Oxidation from 10@super -7@ to 25 Pa: An In-Situ Photoemission Study

Wednesday, November 17, 2004, 9:20 am, Room 210B

Session: Metal Oxides and Clusters I: Formation and Structure
Presenter: D.F. Ogletree, Lawrence Berkeley National Laboratory
Authors: D.F. Ogletree, Lawrence Berkeley National Laboratory
G. Ketteler, Lawrence Berkeley National Laboratory
H. Liu, Lawrence Berkeley National Laboratory
E.L.D. Hebenstreit, Lawrence Berkeley National Laboratory
H. Bluhm, Lawrence Berkeley National Laboratory
M. Salmeron, Lawrence Berkeley National Laboratory
Correspondent: Click to Email
The oxidation of Pd(111) has been studied in equilibrium with oxygen gas between 10@super -7@ and 25 Pa over a temperature range of 300 to 925 K. The experiments were carried out in a newly commissioned, second-generation high pressure photoemission spectroscopy (HPPES) system operating at the Molecular Environmental Sciences synchrotron beamline@footnote 1@. After UHV sample cleaning, the Pd(111) crystal was transferred to a variable pressure experimental cell coupled to a differentially pumped electron spectrometer. High resolution photoemission spectra were recorded for the Pd 3d@sub 5/2@, O1s/Pd3p@sub 1/2@ and valence band regions at different combinations of oxygen pressure and sample temperature. Dynamic and reversible changes in surface oxidation were observed in response to changes in the thermodynamic environment of the palladium substrate. An analysis of the thermodynamics and kinetics of the palladium-oxygen system will be presented. @FootnoteText@ @footnote 1@ Beamline 11.0.2 at the LBNL Advanced Light Source, Berkeley, CA USA.