TY - JOUR
T1 - Adsorption of dimers and trimers of Cu, Ag, and Au on regular sites and oxygen vacancies of the MgO(001) surface
T2 - A density functional study using embedded cluster models
AU - Inntam, Chan
AU - Moskaleva, Lyudmila V.
AU - Neyman, Konstantin M.
AU - Nasluzov, Vladimir A.
AU - Rösch, Notker
PY - 2006/1
Y1 - 2006/1
N2 - We studied the adsorption of small coinage metal aggregates Mn (M = Cu, Ag, Au; n=2,3) on the ideal MgO(001) as well as on oxygen vacancies, Fs and Fs + using a first-principle computational approach. We applied a generalized-gradient density functional in combination with cluster embedding in an elastic polarizable environment, which provides an accurate description of substrate relaxation. In the same way as single adsorbed atoms, metal moieties on regular O2- surface sites are polarized and interact mainly by electrostatic attraction, counteracted by Pauli repulsion. However, adsorption on vacancies involves some transfer of electron density to the adsorbate, particularly for Au2. Our cluster results for Cu2 and Cu3 on regular O2- sites agree quantitatively with previous results of periodic slab models. The adsorption energy per atom decreases from dimers to trimers in line with the fact that metal-metal cohesion dominates over metal-oxide interaction. Compared to regular sites on flat terraces, dimerization is not particularly favorable on Fs sites and it is unfavorable on Fs + sites.
AB - We studied the adsorption of small coinage metal aggregates Mn (M = Cu, Ag, Au; n=2,3) on the ideal MgO(001) as well as on oxygen vacancies, Fs and Fs + using a first-principle computational approach. We applied a generalized-gradient density functional in combination with cluster embedding in an elastic polarizable environment, which provides an accurate description of substrate relaxation. In the same way as single adsorbed atoms, metal moieties on regular O2- surface sites are polarized and interact mainly by electrostatic attraction, counteracted by Pauli repulsion. However, adsorption on vacancies involves some transfer of electron density to the adsorbate, particularly for Au2. Our cluster results for Cu2 and Cu3 on regular O2- sites agree quantitatively with previous results of periodic slab models. The adsorption energy per atom decreases from dimers to trimers in line with the fact that metal-metal cohesion dominates over metal-oxide interaction. Compared to regular sites on flat terraces, dimerization is not particularly favorable on Fs sites and it is unfavorable on Fs + sites.
UR - http://www.scopus.com/inward/record.url?scp=29244486819&partnerID=8YFLogxK
U2 - 10.1007/s00339-005-3352-8
DO - 10.1007/s00339-005-3352-8
M3 - Article
AN - SCOPUS:29244486819
SN - 0947-8396
VL - 82
SP - 181
EP - 189
JO - Applied Physics A: Materials Science and Processing
JF - Applied Physics A: Materials Science and Processing
IS - 1 SPEC. ISS.
ER -