A THEORY OF CONDENSATION AND EVAPORATION OF AEROSOLS.
NAVAL ACADEMY ANNAPOLIS MD DEPT OF ENGINEERING
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The theory described represents a first attempt at devising a model of growth and decay of particles in aerosols which does not depend on the application of properties of the macroscopic condensate to clusters containing only a few molecules. Attention is confined to chemically inert binary mixtures in which one component is a monatomic vapour and the other is a monatomic permanent gas. The principal causes of growth and decay are unimolecular and bimolecular processes described by a canonical ensemble statistics developed from the theory of homogeneous gas reactions. The cohesive force between condensing molecules is pairwise additive, isotropic and of short range, and only the energy exchanged between translations and intermolecular vibrations affects the stability of clusters. Evolution of the aerosol from a specified initial distribution of clusters is described by an expanding chain of simultaneous non-linear rate equations in the concentrations and the time, with coefficients given by the statistics as explicit functions of temperature. These equations are not integrable, but may be solved by computer methods. Equilibrium distributions are obtained by detailed balancing, and show minima defining a cluster size at which isothermal growth is throttled. There is therefore a resemblance to the critical size effect in Volmers theory. Author
- Atomic and Molecular Physics and Spectroscopy