Density Functional Study of Ethylene Adsorption on Palladium Clusters

Fully optimized geometries and adsorption energies obtained from nonlocal density functional calculations are presented for Pd n (C 2 H 4 ) ( n = 1−6) clusters. The adsorption mode can be π or di-σ according to the cluster size. The di-σ adsorption mode is characterized by a strong distortion for both the ethylene and the metal cluster. The potential energy surfaces for the C−H activation show that the d 10 configuration of palladium is suitable for the formation of the π molecular complexes, whereas the d 9 s 1 configuration is suitable for the formation of the σ bonds of the vinyl−hydride products.