Interaction of dihydrogen with transition metal (Pd, Ni, Ag, Cu) clusters

Quantum calculations of interaction of the molecular hydrogen with transition-metal clusters have been performed. The aim of the project is to compare the results for different metals and different methods of calculations. The calculations have been mostly based on the gradient-corrected methods of the density functional theory. The list of the exchange-correlation functionals includes: the gradient corrected functional BP86, the hybrid functionals B3P86, B3LYP, B3PW9, and the local SVWN functional. The calculations of the potential energy surface ( PES) for the hydrogen molecule positioned over the planar Pd-5 clusters have been performed. It was found that the H-H bond activation is without barrier for most of the functionals used. However, the results obtained for the B3LYP functional suggest very small potential barrier, of the order of 0.003 eV. The calculations of the PES for dihydrogen in contact with metal clusters have been performed for Ni-5, Ag-5, Cu-5 clusters and for mixed clusters Ag4Pd, AgPd4, NiCu4, and NiPd4. The dissociation paths for all the cases with the exception of Ag-5 and Cu-5 have been found and the dissociation energies and activation barriers have been estimated.