A kinetic theory of homogeneous bubble nucleation

We present a kinetic theory of homogeneous bubble nucleation based on explicit calculation of the single-molecule evaporation and condensation rates as a function of the size of the vapor embryo. The surface condensation rate is calculated from the kinetic theory of gases, and the surface evaporation rate is related to the rate of escape of molecules from a potential well in the field established by the liquid-vapor interface. Equality of these rates corresponds naturally to the critical bubble. While the interface plays a crucial role in this respect, the kinetic nucleation theory does not invoke an explicit surface tension. The nucleation rate is derived from a population balance and depends only on the ratio of the evaporation to condensation rates. In contrast to classical theory, a nontrivial trend captured by the present theory is the increase in nucleation rate with decreasing temperature at fixed degree of metastability. Comparison with classical nucleation theory reveals markedly different supersaturation dependencies of the nucleation rate, while the predicted sizes of the critical bubble are in good agreement. (C) 2003 American Institute of Physics.