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 firstname.lastname@example.org
Published online: 13 July 2005
The caloric and specific heat curves for the bimetallic nanoclusters AuAgx (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