Eur. Phys. J. D (2013) 67: 132
https://doi.org/10.1140/epjd/e2013-40039-0

Regular Article

Probing the structural and electronic properties of bimetallic Group-III metal-doped gold clusters: Au_nM₂ (M = Na, Mg, Al; n = 1–8)¹

¹ School of Science, East China Institute of Technology, Nanchang 330013, P.R. China
² Institute of Atomic and Molecular Physics, Sichuan University, Chengdu 610065, P.R. China
³ International Centre for Materials Physics, Academia Sinica, Shenyang 110016, P.R. China

^a e-mail: sculyf@163.com

Received: 23 January 2013
Received in final form: 7 March 2013
Published online: 9 July 2013

Abstract

Employing first-principles density functional theory at the PW91PW91 level, the equilibrium geometries, relative stabilities, and electronic properties of bimetallic Au_nM₂ (M  =  Na, Mg, Al; n = 1–8) clusters have been systematically investigated in comparison with pure gold clusters. The optimised results indicate that the doping atom Na trends to occupy a peripheral site in the host, while Mg and Al atoms favour the center site. Furthermore, Al-induced geometries become three-dimensional more easily. Much to our surprise, in the most stable isomers, doping with binary Group-III metal atoms markedly changes the geometries of the ground-state Au_n+2 clusters, and higher average atomic binding energies are found in Al-doped clusters. The calculated fragmentation energies, second-order difference of energies, HOMO-LUMO energy gaps, and chemical hardness as a function of cluster size exhibit a pronounced odd-even alternating phenomenon, suggesting the clusters with closed electronic shells have higher relative stabilities. A natural population analysis has been performed to understand the effects of different doping atoms on electronic properties.