Electronic Properties of Gold Clusters

Gold clusters, comprising anywhere from a few to several dozen atoms, display electronic characteristics that bridge the gap between molecular and bulk behaviour. Their discrete energy levels evolve with size and shape, leading to quantised optical absorption, size-dependent electronic gaps and distinctive magnetic moments. The competition between s- and d-orbitals, combined with relativistic effects in gold, underpins phenomena such as planar-to-three-dimensional structural transitions around 12–14 atoms. Surface interactions and support materials further modulate the electronic states, influencing charge transfer, catalytic activity and stability. Understanding these properties is crucial for applications in heterogeneous catalysis, plasmonic sensing, molecular electronics and energy conversion, where precise control of electron distribution and orbital hybridisation dictates performance.

Research from Nature Portfolio

Recent studies have revealed that the transformation from planar to globular geometries in gold clusters is a gradual process rather than an abrupt size-driven switch. High-throughput density functional theory coupled with evolutionary algorithms demonstrated that van der Waals forces stabilise compact, three-dimensional forms, while s-d band hybridisation alone favours planar motifs. These findings overturn the notion of a sharp transition threshold and highlight the interplay of dispersion interactions, orbital overlap and temperature in determining the electronic ground state of Auₙ clusters around n = 12–14.

Electronic Properties of Gold Clusters publication trend

The graph below shows the total number of articles in electronic properties of gold clusters across all publications each year (not limited to Nature Index journals).

Technical terms

s-d hybridisation: Mixing of gold 6s and 5d orbitals that influences cluster geometry and electronic spectra.

van der Waals interactions: Weak dispersion forces that stabilise compact cluster forms and affect energy ordering.

σ-donation: Electron transfer from a ligand’s lone pair into a metal orbital.

π-back-donation: Electron transfer from a metal d-orbital into a ligand’s antibonding π* orbital.

aromaticity: Delocalisation of electrons in a cyclic arrangement leading to enhanced stability.

density of states: Distribution of available electronic energy levels within a cluster.

References

1. Unraveling the Planar-Globular Transition in Gold Nanoclusters through Evolutionary Search. Scientific Reports (2016).
2. Stabilization of 2D Raft Structures of Au Nanoclusters with up to 60 Atoms by a Carbon Support. Small Science (2024).
3. Formation of pyramidal structures through mixing gold and platinum atoms: the Au x Pt y 2+ clusters with x + y = 10. RSC Advances (2023).
4. Altering CO binding on gold cluster cations by Pd-doping. Nanoscale (2019).