The structure of Au6Y+ in the gas phase

Abstract

The geometric and electronic structure of the Au₆Y⁺ cation is studied by gas phase vibrational spectroscopy combined with density functional theory calculations. The infrared photodissociation spectrum of Au₆Y⁺·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 Au₆Y⁺ is considerably different from those previously found for both the neutral Au₆Y (quasi-planar circular geometry) and the anionic Au₆Y⁻ (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.