THE THEORY OF PHOTONUCLEATION KINETICS

The paper deals with the kinetic theory of cluster formation of a cond ensed phase in supersaturated vapor under laser radiation, Two channel s of the photonucleation kinetics are defined. The kinetic equations f or the distribution function of the cluster size are derived using the methods of nonequilibrium statistical thermodynamics. The first chann el involves direct heat impact of the laser radiation on the cluster o f a condensed phase. The second channel of photonucleation deals with resonance excitation of vapor molecules under the effect of laser radi ation at the specific of wavelength and deactivation of internal degre es of freedom of the vapor molecules during collisions with the cluste r surface. The important dimensionless groups of physical parameters, which characterize these channels of photonucleation, are obtained. So me results of a numerical investigation of the steady-state photonucle ation kinetics are presented, In particularly, it is shown in the fram e of the discussed physical models, that laser radiation usually decre ases the nucleation rate. For cases where the second mechanism (channe l) of photonucleation is the most important, the theory predicts the e xistence a state when the opposite effect takes place, i.e. the nuclea tion rate is enhanced.