Binary nucleation kinetics. V. Phi lines and evaporation rate surfaces

We explore the quasiuniversal behavior of the function Phi(i,j,t) = f(i,j,t )/N(i,j,t) in binary nucleation, where f(i,j,t) and N(i,j,t) are the nonequ ilibrium and equilibrium cluster concentrations, respectively. The simple, regular patterns that are formed by this function during both the transient period and at steady state suggest that the contour lines of constant Phi form one half of a natural curvilinear coordinate system that underlies the binary nucleation process. In this paper we present the Phi-Line patterns for binary systems that display a wide range of liquid phase nonideality. Q uantitative comparisons between analytical expressions for the angle that d el Phi makes with the component A axis and for the spacing of the Phi conto ur lines give good agreement with the values derived from the numerical sol ution of the binary kinetics equations. The insensitivity of the Phi-line p atterns to changes in the gas phase activities of the nucleating species ca n be better understood by writing the binary kinetics equations with the ev aporation rate coefficients as the "difffrsion coefficients." In this form it is easy to see that the equations only depend weakly on the actual gas p hase compositions. (C) 1999 American Institute of Physics. [S0021-9606(99)5 1402-5].