  More than a century has passed since van't Hoff and Arrhenius formulated
their celebrated rate theories, but there are still elusive aspects in the
temperature-dependent phase transition kinetics of molecular systems. Here I
present a theory based on microcanonical thermostatistics that establishes a
simple and direct temperature dependence for all rate constants, including the
forward and the reverse rate constants, the equilibrium constant, and the
nucleation rate. By considering a generic model that mimic the microcanonical
temperature of molecular systems in a region close to a first-order phase
transition, I obtain shape-free relations between kinetics and thermodynamics
physical quantities which are validated through stochastic simulations.
Additionally, the rate theory is applied to results obtained from protein
folding and ice nucleation experiments, demonstrating that the expressions
derived here can be used to describe the experimental data of a wide range of
molecular systems.
