Eur. Phys. J. D 56, 189-197 (2010)
https://doi.org/10.1140/epjd/e2009-00295-1

Structural and electronic properties of small bimetallic Ag–Cu clusters

Department of Materials Science and Engineering, University of Ioannina, POB 1186, 45110 Ioannina, Greece

Corresponding author: dpapageo@cc.uoi.gr

Received: 16 June 2009
Revised: 16 October 2009
Published online: 24 November 2009

Abstract

The structural and electronic properties of small gas-phase Ag_mCu_n clusters with m+n=2–5 atoms are investigated using spin-polarized density functional theory. The LANL2DZ effective core potential and the corresponding basis set are employed while the performance of several exchange-correlation functionals is assessed. For a given cluster size all possible compositions are subject to optimization using a variety of initial structures. The geometry, binding energy, relative stability, ionization potential, electron affinity and HOMO-LUMO gap are reported for the lowest energy structure of every cluster size and composition. The results show that planar structures are favored, triangular for trimers, rhombic for tetramers and trapezoidal for pentamers. Moreover, for tetramers and pentamers we found that silver atoms demonstrate a clear tendency to occupy edge positions. The calculation of electronic properties indicates that although all exchange-correlation functionals predict the same trends, the choice of method is crucial concerning the final quantitative results.