THE INITIATING RATE OF A HETEROGENEOUS REACTION

A stochastic model of nucleation and subsequent growth of new phase is lands on solid surfaces is proposed and expressions for the mean induc tion time and its variance are obtained in an explicit form. The inter mediate stage of the new surface phase evolution is studied under cond itions of the supersaturation gradually decreasing as a result of the growth of the islands. The island size distribution as well as the sup ersaturation and the fraction of the surface area covered with the new phase are found as functions of time. It is proved that both the indu ction period and decrease in surface metastability must be taken into account when trying to treat the surface reaction kinetics, and some c onclusions of conventional models with no allowance for the aforementi oned factors have certainly to be revised.