Non-additive effects in small gold clusters

A post-Hartree-Fock second-order perturbational Moller-Plesset method was u sed to determine the many-body contributions in the interaction energy of A u-n(n = 3-6), clusters. Non-additive effects in these clusters were studied by decomposing the cluster binding energy in their n-body energy terms. It was found that the non-additive forces in small gold clusters are larger t han the additive 2-body interactions and are the main factor to stabilize p lanar two-dimensional geometries as the lowest energy isomers. The effect o f electron correlation in the interaction energy n-body decomposition was a lso analyzed and found to be important. (C) 1999 Elsevier Science B.V. All rights reserved.