We report an unexpectedly strong and complex chemical bonding of rare-gas
atoms to neutral gold clusters. The bonding features are consistently
reproduced at different levels of approximation within density-functional
theory and beyond: from GGA, through hybrid and double-hybrid functionals, up
to renormalized second-order perturbation theory. The main finding is that the
adsorption of Ar, Kr, and Xe reduces electron-electron repulsion within gold
dimer, causing strengthening of the Au-Au bond. Differently from the dimer, the
rare-gas adsorption effects on the gold trimer's geometry and vibrational
frequencies are mainly due to electron occupation of the trimer's lowest
unoccupied molecular orbital. For the trimer, the theoretical results are also
consistent with far-infrared multiple photon dissociation experiments.Comment: To be published in Inorganic Chemistry Communication
