  Four basic processes are envisioned, among them migration (diffusion), local
rotation (reorientation), isothermic chemical reactions and nucleation. All of
them are unified by a common approach to the barrier currents that has been
suggested as far back as 1961 by John Bardeen and then extended by Stefan
Christov some ten years later. By introducing the respective radial potentials,
we incorporate Schroedinger's equation and thereby a quantum insight into the
phenomena. Numerical calculations of the obtained statistical transition rates
are reported.
