Bulk-fragment and tube-like structures of AuN (N=2-26)

TL;DR

This study uses density-functional calculations to explore the structural evolution of gold clusters AuN (N=2-26), revealing a transition from 2D to 3D structures and identifying tubelike configurations as most stable for certain sizes due to relativistic effects.

Contribution

It provides new insights into the structural preferences and stability of gold clusters, highlighting the significance of relativistic effects and discovering tubelike structures as energetically favorable.

Findings

2D to 3D transition occurs between N=13 and 15.

Tubelike structures are most stable for Au24 and Au26.

Relativistic effects enhance s-d hybridization and d-d interactions.

Abstract

Using the relativistic all-electron density-functional calculations on the AuN (N=2-26) in the generalized gradient approximation, combined with the guided simulated annealing, we have found that the two- to three-dimensional structural transition for AuN occurs between N=13 and 15, and the AuN (16<= N <=25) prefer also the pyramid-based bulk fragment structures in addition to the Au20. More importantly, the tubelike structures are found to be the most stable for Au24 and Au26, offering another powerful structure competitor with other isomers, e.g., amorphous, bulk fragment, and gold fullerene. The mechanism to cause these unusual AuN may be attributed to the stronger s-d hybridization and the d-d interaction enhanced by the relativistic effects.