Efficient approximation of the cluster size distribution in binary condensation

We propose a computationally efficient method for the calculation of the binary cluster size distribution. This method is based on the phase path analysis algorithm, which was originally derived for single-component condensation. We extend this method by constructing the binary general dynamic equation, which introduces clusters at a point in two component n(1),n(2)-space. The location of this source point is determined by the Gibbs free energy of formation and the impingement rates of the two constituents. The resulting model describes the binary cluster size distribution along a line in n(1),n(2)-space. The solution of the binary general dynamic equation is compared with the solution of formally exact binary Becker-Doumlring equations for a typical nucleation pulse experiment. The results show good agreement for the cluster composition and size and the integral properties of the size distribution. (C) 2010 American Institute of Physics. [doi:10.1063/1.3429881]