https://doi.org/10.1140/epjd/e2005-00140-7
Thermodynamic properties of AuyAgx bimetallic clusters through the evolutive ensemble
Instituto de Física, Universidad Nacional Autónoma
de México, A.P. 20-364, 01000 México D.F., México
Corresponding author: a karo@fisica.unam.mx
Received:
6
September
2004
Published online:
13
July
2005
The caloric and specific heat curves for the bimetallic nanoclusters Au
Agx (x=0,3,4,7) are obtained through a statistical determination
of the configurational density of states in the evolutive ensemble
obtained with a genetic algorithm. The effect of the value of x
(the relative concentrations) on the thermodynamics is studied.
Three peaks are observed in the specific heat curves for all values
of x. This is interpreted as being due to melting, and fragmentation
of the cluster into first two, and then into 3 or more parts.
A fourth pre-melting peak is observed for Au4Ag3 and is
attributed to a new phenomena related to the breaking of the
degeneracy of the permutational isomers. The
melting transition for the bimetallic clusters is significantly
wider than that for the pure clusters. The
boiling transition displays a larger specific heat for the
bimetallic clusters.
PACS: 36.40.Ei – Phase transitions in clusters / 36.40.-c – Atomic and molecular clusters
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2005
