Static, statistical, and dynamical properties of small sodium clusters

Romuald Poteau (1) , Daniel Maynau (1) , Jean-Pierre Daudey (1) , Fernand Spiegelman (1)

1 LPQ - Laboratoire de Physique Quantique

This paper reports results obtained in the study of small alkali metal clusters (2_10), technical difficulties related with the increase of the degrees of freedom did occur, worsened by the strong degeneracy of the various isomers and the flexible character of metallic clusters. In order to circumvent this problem, we have adapted [4] for sodium clusters a Monte-Carlo technique which is not based on statistical trajectories, but on statistical growth and which was initially developed and checked for biological systems [5]. Let us suppose that the sampling for a given cluster size n is already boltzmanian, e.g., the number of configurations with geometry Qi n in the sampling obeys the Boltzmann law : M(Q~)= Anexp[-~E(Qn)] with fl = l / kT where An is a normalization factor and E(Qi n) the energy of the configuration Qi n. Then, the sampling for size n+l is achieved from the various configurations Qi n by adding an atom and so generating a configuration Qjn+l. This new configuration is replicated according to a conditional probability law of obtaining Q1 ~+1 from Q~ : w'~n+lt ~n" e x " °'E'~n+l" t~d) ~di)= Pt-Pt t~j)-E(an))] In practical, since the replication factor must be integer, one uses a replication factor : mn+l = Pn+l + rn+l with : Pn+l = Int(w) {~ if W-pn+l < v rn+l = if W-Pn+l > V where v is a random number (Nv<_l. As a consequence, M(Qj n+l) also follows Boltzmann's law. Details about the

Domaines: Chimie théorique et/ou physique

Romuald Poteau, Daniel Maynau, Jean-Pierre Daudey, Fernand Spiegelman. Static, statistical, and dynamical properties of small sodium clusters. Zeitschrift für Physik D Atoms, Molecules and Clusters, 1993, 26 (1-4), pp.232 - 235. ⟨10.1007/BF01429154⟩. ⟨hal-01755338⟩