Open AccessGeometry of α-Cr2O3(0001) as a Function of H2O Partial Pressure
Author(s) -
M. Ahmed,
X. Torrelles,
Jon Treacy,
Hadeel Hussain,
Chris Nicklin,
P.L. Wincott,
David J. Vaughan,
G. Thornton,
R. Lindsay
Publication year - 2015
Publication title -
the journal of physical chemistry c
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.401
H-Index - 289
eISSN - 1932-7455
pISSN - 1932-7447
DOI - 10.1021/acs.jpcc.5b04607
Subject(s) - adsorption , partial pressure , diffraction , atom (system on chip) , desorption , langmuir , ab initio , chromium , chemistry , surface (topology) , crystallography , materials science , analytical chemistry (journal) , atomic physics , geometry , physics , oxygen , metallurgy , optics , organic chemistry , chromatography , computer science , embedded system , mathematics
Surface X-ray diffraction has been employed to elucidate the surface structure of α-Cr 2 O 3 (0001) as a function of water partial pressure at room temperature. In ultra high vacuum, following exposure to ∼2000 Langmuir of H 2 O, the surface is found to be terminated by a partially occupied double layer of chromium atoms. No evidence of adsorbed OH/H 2 O is found, which is likely due to either adsorption at minority sites, or X-ray induced desorption. At a water partial pressure of ∼30 mbar, a single OH/H 2 O species is found to be bound atop each surface Cr atom. This adsorption geometry does not agree with that predicted by ab initio calculations, which may be a result of some differences between the experimental conditions and those modeled.
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