Kramers rate theory of ionization and dissociation of bound states

TL;DR

This paper introduces a new classical theory for calculating dissociation rates of bound states without energy barriers, accounting for entropic memory, and applies it successfully to plasma ionization and biological processes.

Contribution

The paper develops a novel classical Kramers rate theory that includes entropic memory effects, applicable to systems lacking traditional energy barriers.

Findings

Accurately predicts plasma ionization rates in the Sun's core.

Accounts for crowding effects in receptor-ligand kinetics.

Matches experimental data for dissociation in various systems.

Abstract

Calculating the microscopic dissociation rate of a bound state, such as a classical diatomic molecule, has been difficult so far. The problem was that standard theories require an energy barrier over which the bound particle (or state) escapes into the preferred low-energy state. This is not the case when the long-range repulsion responsible for the barrier is either absent or screened (as in Cooper pairs, ionized plasma, or biomolecular complexes). We solve this classical problem by accounting for entropic memory at the microscopic level. The theory predicts dissociation rates for arbitrary potentials and is successfully tested on the example of plasma, where it yields an estimate of ionization in the core of Sun in excellent agreement with experiments. In biology, the new theory accounts for crowding in receptor-ligand kinetics and protein aggregation.