Electronic shell structure and chemisorption on gold nanoparticles

TL;DR

This study uses density functional theory to analyze the electronic shell structure and chemisorption properties of gold nanoparticles, revealing how cluster geometry and magic numbers influence electronic properties and adsorption energies.

Contribution

It provides new insights into the electronic shell structure and chemisorption behavior of gold nanoparticles across different geometries and sizes, using DFT and a Newns-Anderson model.

Findings

Cluster geometries distort significantly, creating large band gaps.

All cluster types exhibit jellium-like electronic shell structure.

Adsorption energies vary abruptly at magic numbers.

Abstract

We use density functional theory (DFT) to investigate the electronic structure and chemical properties of gold nanoparticles. Different structural families of clusters are compared. For up to 60 atoms we optimize structures using DFT-based simulated annealing. Cluster geometries are found to distort considerably, creating large band gaps at the Fermi level. For up to 200 atoms we consider structures generated with a simple EMT potential and clusters based on cuboctahedra and icosahedra. All types of cluster geometry exhibit jellium-like electronic shell structure. We calculate adsorption energies of several atoms on the cuboctahedral clusters. Adsorption energies are found to vary abruptly at magic numbers. Using a Newns-Anderson model we find that the effect of magic numbers on adsorption energy can be understood from the location of adsorbate-induced states with respect to the cluster Fermi level.