Kinetic eects in a non-ideal gas of clusters

The kinetic properties of clusters are studied taking into account non-ideal contributions. The velocity distribution functions are distorted Maxwellians. From these distributions it is possible to derive kinetic \temperatures " associated with each cluster species which are dierent from the thermodynamic temperature T. Molecular dynamics simulations conrm these predictions and show that the kinetic temperatures are larger than T. c © 1998 Elsevier Science B.V. All rights reserved. Molecules in a gas at equilibrium, and not too far from the liquid{gas transition, tend to form microscopic clusters. Clusters can be thought of as microscopic domains of the liquid phase. The study of the cluster properties is essential for understanding the condensation phenomena [1]. A lot of work has been done in predicting the clusters free energy [2] and their kinetic properties [3]. The eect of excluded volume is treated in [4]. In a recent paper, a new formalism based on a virial expansion that predicts the non-ideal eects in the concentration of clusters is used [5]. This formalism shows good agreement with molecular dynamics simulations