Argon Adsorption on Cationic Gold Clusters Au<i>_n</i>⁺ (<i>n</i> ≤ 20)

• Main Authors: Piero Ferrari, Ewald Janssens
• Format: Article
• Language: English
• Published: MDPI AG 2021-07-01
• Series: Molecules
• Subjects: gold clusters; argon; adsorption energies; mass spectrometry; density functional theory
• Online Access: https://www.mdpi.com/1420-3049/26/13/4082
• ISSN: 1420-3049

The interaction of Au<i>_n</i>⁺ (<i>n</i> ≤ 20) clusters with Ar is investigated by combining mass spectrometric experiments and density functional theory calculations. We show that the inert Ar atom forms relatively strong bonds with Au<i>_n</i>⁺. The strength of the bond strongly varies with the cluster size and is governed by a fine interplay between geometry and electronic structure. The chemical bond between Au<i>_n</i>⁺ and Ar involves electron transfer from Ar to Au, and a stronger interaction is found when the Au adsorption site has a higher positive partial charge, which depends on the cluster geometry. Au₁₅⁺ is a peculiar cluster size, which stands out for its much stronger interaction with Ar than its neighbors, signaled by a higher abundance in mass spectra and a larger Ar adsorption energy. This is shown to be a consequence of a low-coordinated Au adsorption site in Au₁₅⁺, which possesses a large positive partial charge.