Eur. Phys. J. D 63, 111-122 (2011)
https://doi.org/10.1140/epjd/e2011-20055-x

Regular Article

Structural, electronic and magnetic properties of Au_nPt (n = 1−12) clusters in comparison with corresponding pure Au_n+1 (n = 1−12) clusters

¹ College of Physics, Chongqing University, Chongqing 400044, P.R. China
² School of Science, Southwest University of Science and Technology, Mianyang, Sichuan 621010, P.R. China

^a e-mail: xkdkxj@yahoo.com.cn

Received: 22 January 2011
Received in final form: 11 March 2011
Published online: 17 May 2011

Abstract

An all-electron scalar relativistic calculation on Au_nPt (n = 1−12) clusters has been performed by using density functional theory with the generalized gradient approximation at PW91 level. Our results reveal that all the lowest energy geometries of Au_nPt  (n = 1−12) clusters may be generated by substituting Pt atom for one gold atom of the Au_n+1 cluster at the highest coordinated site. Compared with corresponding pure Au_n+1 cluster, the lowest energy geometries of Au_nPt clusters are distorted slightly and still keep the planar structures due to the strong scalar relativistic effect in small gold cluster. The Au-Pt bonds are stronger and most Au-Au bonds far from Pt atom are weaker than the corresponding Au-Au bonds in pure Au_n+1 cluster. By substituting Pt atom for one gold atom of Au_n+1 cluster at the highest coordinated site, the relatively stable and inactive odd-numbered Au_n+1 cluster becomes the relatively unstable and reactive odd-numbered Au_nPt cluster, and the relatively unstable and reactive even-numbered Au_n+1 cluster becomes the relatively stable and inactive even-numbered Au_nPt  cluster chemically and electronically. All the Au_nPt clusters prefer low spin multiplicity. The even-numbered Au_nPt clusters are found to exhibit zero magnetic moment and the odd-numbered Au_nPt clusters are found to possess magnetic moment with the value of 1 μ_B. The odd-even alterations of magnetic moments and electronic configurations for Au_nPt clusters are very obvious and may be simply understood in terms of the electron pairing effect.