title: Theoretical studies for structures and energetics of Rgn-N2O (Rg=He, Ne, Ar) clusters.
abstract: Minimum-energy structures of the Rg(2)-N(2)O (Rg=He, Ne, Ar) clusters have been determined with ab initio MP2 optimization, whereas the minimum-energy structures of the Rg(n)-N(2)O clusters with n = 3-7 have been obtained with the pairwise additive potentials. Interaction energies and nonadditive three-body effects of the Rg(2)-N(2)O ternary complex have been calculated using supermolecule method at MP4 and CCSD(T) levels. It was found from the calculations that there are two minima corresponding to one distorted tetrahedral structure and one planar structure for the ternary complex. The nonadditive three-body effects were found to be small for Rg(2)-N(2)O complexes. Our calculations also indicated that, for He(n)-N(2)O and Ne(n)-N(2)O clusters, the first six He and Ne atoms form the first solvation ring around the middle nitrogen of the N(2)O monomer, while for Ar(n)-N(2)O, the first five Ar atoms form the first solvation ring.