MICROSCOPIC REVERSIBILITY AND THE NONLINEAR EINSTEIN-ONSAGER RELATIONIN MACROSCOPIC DESCRIPTION OF NUCLEATION

We investigate the possibility of describing fluctuational decay of a metastable phase macroscopically, without a detailed knowledge of the microscopic kinetics. Using the ideas of microscopic reversibility, we construct a hydrodynamic-type equation which describes the buildup of fluctuations in the region of subcritical sizes. An equation of Ornst ein-Uhlenbeck type is used to bridge this equation with the one descri bing unstable growth of larger (overcritical) fluctuations. An explici t time-dependent solution to the proposed system of equations is deriv ed in the spirit of the singular perturbation technique. It is shown t hat this solution also accurately approximates the solution of the Far kas-Becker-Doring master equation, so that the macroscopic level of de scription is consistent with the underlying models.