Non-activated metal cluster growth during nozzle jet expansion

Based on the classical liquid-drop nucleation theory for small clusters, we show quantitatively the existence of a boundary which separates the nucleation and growth and non-activated (physical spinodal) cluster growth regions for supersaturated vapors. We found that for the expansion geometry such as the one used by Yamada and Takagi in their nozzle jet experiments for producing metal clusters, the non-activated growth process may play an important, if not predominant, role in the growth of clusters.