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Hydrogen chemisorption on, and diffusion through, palladium clusters
Author(s) -
Baykara N. A.,
Andzelm J.,
Salahub D. R.,
Baykara S. Z.
Publication year - 1986
Publication title -
international journal of quantum chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.484
H-Index - 105
eISSN - 1097-461X
pISSN - 0020-7608
DOI - 10.1002/qua.560290437
Subject(s) - chemisorption , chemistry , hydrogen , palladium , octahedron , cluster (spacecraft) , diffusion , crystallography , atomic physics , catalysis , physics , thermodynamics , crystal structure , adsorption , biochemistry , organic chemistry , computer science , programming language
LCGTO ‐ VWN ‐ MP calculations have been performed for PdH, Pd 3 H, and for a series of Pd 10 H clusters representing hydrogen chemisorbed on a (111) surface and at various sites along a diffusion path through the cluster. The calculated chemisorption geometry (over a threefold site) has a PdH distance of 1.72 Å, slightly longer than that proposed by Eberhardt et al. (1.69 Å) on the basis of comparison of photoemission data with slab calculations. Agreement with known energy differences is very good: We find the chemisorption site 0.25 eV (exp. 0.26) more stable than the most stable (octahedral) bulk site. The top of the diffusion barrier, a triangular site, is calculated 0.34 eV (exp. 0.23) above the octahedral site. All the sites have a split‐off state of Pd d, H s character below the d bands, indicating that the ‘invisible’ state of H/Pd(111) recently (not) observed in UPS cannot straightforwardly be attributed to hydrogen incorporation at sites such as these.