Potential energy barriers in the kinetic theory of nucleation

摘要

The problem of partition of the transition free energy dgr;famong the potential barriers for cluster growth (U+iminus;1) and dissociation (Uminus;i) is discussed. The proposed simple solutionsU+iminus;1=egr;+zdgr;fi,Uminus;i=egr;minus;(1minus;z)dgr;fi, andz= 1/2 lsqb;1+sign(dgr;fi)rsqb; satisfy all requirements imposed on the problem. Consequently, in the nucleation theory two different critical cluster sizes appear:i@B0, which corresponds to the change of sign of dgr;fiand transition in the potentialsU+iminus;1,Uminus;i, andiast; (generally different fromiast;0), which accounts for nucleation rate.