Au₁₄₇ nanoparticles: Ordered or amorphous?

Area of Science:

• Computational Chemistry
• Materials Science
• Nanotechnology

Background:

• Understanding the structural diversity of gold nanoclusters is crucial for predicting their behavior.
• The competition between ordered and disordered structures influences cluster stability and properties.

Purpose of the Study:

• To investigate the structural characteristics of the gold 147 (Au₁₄₇) cluster.
• To explore the relevance of amorphous geometries in the finite temperature dynamics and thermodynamics of Au₁₄₇.

Main Methods:

• Global optimization using density functional based tight binding (DFTB) with parallel tempering molecular dynamics.
• Geometry relaxation at the Density Functional Theory (DFT) level.
• Analysis of structural parameters including anisotropy, coordination numbers, radial distribution functions, IR spectra, and vibrational density of states (DOS).

Main Results:

• Amorphous Au₁₄₇ geometries are identified as relevant low-energy candidates.
• Amorphous structures exhibit a higher surface-to-volume ratio, lower coordination numbers, increased surface facets, and greater anisotropy compared to ordered structures.
• Amorphous clusters show broad, continuous IR spectra, while symmetric clusters display distinct, intense spectral lines.

Conclusions:

• Disordered (amorphous) structures play a significant role in the finite temperature behavior of Au₁₄₇ clusters.
• The distinct structural and vibrational properties of amorphous Au₁₄₇ suggest unique reactivity and potential applications.