Clustercollision frequency. I. The longrange intercluster potential.
Academic Article

 Overview

 Identity

 Additional Document Info

 View All

Overview
abstract

In recent years, gasborne atomic and molecular clusters have emerged as subjects of basic physical and chemical interest and are gaining recognition for their importance in numerous applications. To calculate the evolution of the mass distribution of these clusters, their thermal collision rates are required. For computing these collision rates, the longrange interaction energy between clusters is required and is the subject of this paper. Utilizing a formulation of the iterated van der Waals interaction over discrete molecules that can be shown to converge with increasing numbers of atoms to the Lifshitzvan der Waals interaction for condensed matter, we calculate the interaction energy as a function of centerofmass separation for identical pairs of clusters of 13, 33, and 55 molecules of carbon tetrachloride in icosahedral and dodecahedral configurations. Two different relative orientations are chosen for each pair of clusters, and the energies are compared with energies calculated from the standard formula for continuum matter derived by summing over pair interactions with the Hamaker constant calculated according to Lifshitz theory. The results of these calculations give longrange interaction energies that assume typical adhesiontype values at cluster contact, unlike the unbounded results for the LifshitzHamaker model. The relative difference between the discrete molecular energies and the continuum energies vanishes for r*2, where r* is the centerofmass separation distance in units of cluster diameter. For larger separations, the relative difference changes sign, showing a value of approximately 15%, with the difference diminishing for increasingsized clusters. We argue that the details of the results of these calculations indicate that the deficiency in the continuum picture for small separations lies in the substitution of an averaged picture of the interaction for what is intrinsically the cumulative energy of discrete interactants. © 1991 The American Physical Society.
published proceedings
author list (cited authors)

Amadon, A. S., & Marlow, W. H
citation count
complete list of authors
publication date
publisher
published in
Identity
PubMed Central ID
Digital Object Identifier (DOI)
Additional Document Info
start page
end page
volume
issue