The structure of Au(6)Y(+) in the gas phase.

The geometric and electronic structure of the Au(6)Y(+) cation is studied by gas phase vibrational spectroscopy combined with density functional theory calculations. The infrared photodissociation spectrum of Au(6)Y(+)·Ne is measured in the 95-225 cm(-1) energy range and exhibits two characteristic absorption bands at 181 cm(-1) and 121 cm(-1). Based on DFT/BP86 quantum chemical calculations, the infrared spectrum is assigned to the lowest energy species found, an eclipsed C(3v) geometry. The 3D structure of Au(6)Y(+) is considerably different from those previously found for both the neutral Au(6)Y (quasi-planar circular geometry) and the anionic Au(6)Y(-) (planar D(6h) symmetry). The different geometries are related to different electronic structures in agreement with 2D and 3D phenomenological shell models for metal clusters.