| Abstract
| - The nature of the chemical bond between gold and the noble gases in the simplest prototype ofAu(I) complexes (NgAuF and NgAu+, where Ng = Ar, Kr, Xe), has been theoretically investigated by stateof art all-electron fully relativistic DC-CCSD(T) and DFT calculations with extended basis sets. The mainproperties of the molecules, including dipole moments and polarizabilities, have been computed and adetailed study of the electron density changes upon formation of the Ng−Au bond has been made. TheAr−Au dissociation energy is found to be nearly the same in both Argon compounds. It almost doublesalong the NgAuF series and nearly triples in the corresponding NgAu+ series. The formation of the Ng−Au(I) bonds is accompanied by a large and very complex charge redistribution pattern which not only affectsthe outer valence region but reaches deep into the core−electron region. The charge transfer from thenoble gas to Au taking place in the NgAu+ systems is largely reduced in the fluorides but the Ng−Auchemical bond in the latter systems is found to be tighter near the equilibrium distance. The density differenceanalysis shows, for all three noble gases, a qualitatively identical nature of the Ng−Au bond, characterizedby the pronounced charge accumulation in the middle of the Ng−Au internuclear region which is typical ofa covalent bond. This bonding density accumulation is more pronounced in the fluorides, where the Au−Fbond is found to become more ionic, while the overall density deformation is more evident and less localizedin the NgAu+ systems. Accurate density difference maps and charge-transfer curves help explain verysubtle features of the chemistry of Au(I), including its peculiar preference for tight linear bicordination.
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