Genuine saddle point in binary nucleation kinetics

We construct a generalized nucleation potential for binary systems, which includes both the thermodynamic and kinetic effects. We show that the major nucleation flux passes through the saddle point (termed the genuine saddle point) of this generalized nucleation potential, even if it no longer passes through the thermodynamic saddle point. The genuine saddle point concept provides a convenient way to identify systems and conditions for which the ridge crossing phenomenon occurs. Our theory agrees approximately with exact numerical results.