CO在M55（M=Cu,Ag,Au）团簇上吸附的密度泛函研究

在全电子相对论BVP86/DNP水平下对CO在Au55,Ag55和Cu55团簇上的吸附进行了比较研究,并考察了电荷对吸附的影响.计算结果表明,CO在Au55团簇上吸附能最大,其次为Cu55团簇,最弱的为Ag55团簇.团簇电荷对C—O键活化和CO与团簇表面原子成键影响较小.金团簇的电荷对吸附能影响较大,而银和铜团簇的电荷对吸附能影响较小.CO吸附到团簇上导致团簇上电子向CO转移.C—O键活化强度与吸附位置密切相关,其中孔位吸附导致C—O键活化程度最大,最弱的为顶位吸附.CO在金团簇上吸附具有较好选择性,而在银和铜团簇上吸附无选择性.

Density Functional Studies of CO Adsorption on M55 （M=Cu, Ag, Au） Clusters

The carbon monoxide adsorption onto the Au55,Ag55,and Cu55clusters were comparably investigated at the all-electron relativistic BVP86/DNP levels.The charge effects of CO adsorption also were studied.The computational results indicated that CO adsorption energies on the Au55 clusters are maximum,followed by those on the Cu55 clusters,the minimum for those on the Ag55 clusters.The cluster’s charge affects slightly the activation of C—O bond and the bond strength between the carbon atom of CO and the surface atoms of cluster.The CO adsorption onto the clusters results in the charge transfer from cluster to CO fragment.The activation of C—O bond is closely related to the adsorption site of CO.The activation order of C—O bond for the CO adsorption on the different site of the cluster as follows: hole site>bridge site>top site.The CO can be selectively adsorbed at the top site of Au55 clusters,while the CO adsorption on Ag55and Cu55clusters is non-selective.