Probing structures of small gold cluster cations with dinitrogen.

Area of Science:

• Physical Chemistry
• Materials Science
• Nanotechnology

Background:

• Gold cluster cations (Au(n)(+)) are studied for their unique chemical and physical properties.
• Understanding the adsorption behavior of small metal clusters is crucial for catalysis and materials design.

Purpose of the Study:

• To investigate the adsorption of nitrogen molecules (N(2)) on small gold cluster cations.
• To determine the geometrical structures of gold cluster cations based on their N(2) adsorption saturation numbers.
• To explore the size-dependent structural transitions in gold cluster cations.

Main Methods:

• Multiple collision conditions were used to study N(2) adsorption on Au(n)(+).
• Saturation numbers of N(2) adsorption were measured to infer cluster structures.
• Analysis of adsorption data was used to identify isomers and structural transitions.

Main Results:

• N(2) adsorption saturation on Au(n)(+) depends on dangling gold atoms and triangular apexes.
• Gold cluster cations of sizes 3 and 6 exhibit single isomers, while sizes 4, 5, and 7 show two isomers.
• A higher-energy, lower-symmetry structure was observed for Au(6)(+).
• Au(n)(+) with n >= 8 do not adsorb N(2), indicating a 2D to 3D structural transition at n = 8.

Conclusions:

• The N(2) adsorption method effectively probes the geometrical structures of small gold cluster cations.
• Size-dependent isomerism and a significant structural transition occur in gold cluster cations.
• The findings provide insights into the fundamental properties of gold nanoclusters.