Kinetic theory of steady chemical nucleation in the gas phase

We develop a kinetic theory of nucleation involving chemical reactions in t he gas phase. For the basis of deriving the chemical nucleation rate, chemi cal kinetic considerations are presented on the steady current density and the effective rate constants of the overall reaction, which is a sum of a s equential elementary reactions. We formulate the steady rate of chemical nu cleation in a multi-component vapor, in which nucleation occurs via the che mical reactions yielding a condensate having a stoichiometric composition. An exact expression of the steady nucleation rate is given together with it s approximate formulas for practical applications. The present formulation is not concerned with any particular cluster model. The supersaturation rat io for a many-component vapor is defined so as to be a natural extension of that for a one-component vapor. It is shown that the transition probabilit ies due to growth and decay of the clusters are of the same form as the gro wth and evaporation rates in a one-component vapor.