Photoinduced nucleation in supersaturated mercury vapor

Photoinduced nucleation of mercury vapor is studied experimentally in an upward thermal diffusion cloud chamber. The rate of nucleation is greatly increased when the supersaturated vapor is illuminated with light absorbed by the vapor molecules. In analogy to ion-induced nucleation the photoinduced nucleation can be explained as a general effect for all condensing atoms or molecules forming long living; electronically excited states, (C) 1998 American Institute of Physics.