General approach to barrier crossing in multicomponent nucleation

Multicomponent nucleation analysis is reformulated to include all paths of nucleation. Starting with simple measurement theory, one is led to define a global nucleation rate that corresponds to what is observable experimentally. This rate can be calculated at steady state and estimated for arbitrary times, provided the rate matrix and the free energy obey certain constraints. When applied to the special case of a quadratic barrier, the global nucleation rate is smaller than the standard result based on the rate of saddle-point nucleation. Cases with more general barriers can also be treated by the same method.