Eur. Phys. J. D (2013) 67: 33
https://doi.org/10.1140/epjd/e2012-30447-y

Regular Article

Structural and electronic properties of TM_{23 - p}Ag_p (TM = Ni, Pd, and Pt) clusters in the dilute limit (p = 0–4): A density functional theory investigation

¹ Instituto de Física, Universidad Autónoma de San Luis Potosí, 78000 San Luis Potosí, México
² Instituto de Química de São Carlos, Universidade de São Paulo, Caixa Postal 780, 13560-970 São Carlos, SP, Brazil
³ Instituto de Física de São Carlos, Universidade de São Paulo, Caixa Postal 369, 13560-970 São Carlos, SP, Brazil

^a e-mail: faustino@ifisica.uaslp.mx

Received: 17 July 2012
Received in final form: 18 December 2012
Published online: 6 March 2013

Abstract

We studied the structural, energetic, and electronic properties of free-standing binary clusters in the dilute limit, TM_23 − pAg_p with TM = Ni, Pd, and Pt, and p = 0–4, employing density functional theory within the generalized gradient approximation to the exchange-correlation energy functional, as implemented in the SIESTA code. For all studied systems, we found that the addition of Ag impurities decreases the binding energy of the clusters. The Ag impurities always prefer the surface sites, although not always the lowest coordination sites are occupied as it is observed in Pt, where large coordination surface sites are in general preferred. Clear Ag segregation is observed in Ni with the poly-icosahedral structure and Pt in the cubic-pyramidal structure. For Pd case a weak segregation and mixing patterns coexist depending upon which structure is shown, in the other cases in general a tendency to mixing is presented.