The applicability and reliability of the ONIOM framework in modeling metal
surface were first examined in the present study. Both two- and three-layer
ONIOM methodology are found economical and reliable. The first nearest coo
rdinate metal atoms of those forming adsorption sites, which play a key rol
e in determining the adsorption energies, are required to be described by a
n accurate high level method, while a low level method can be applied to th
e second nearest neighbor or farther atoms. (C) 2000 Elsevier Science B.V.
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