Diffusive barrier crossing and friction
Research context
postgraduate concept · conditional · As of 2026-10-10
In an overdamped diffusive reaction-coordinate model, the flux contains both potential-driven drift and concentration spreading.
Key knowledge
In an overdamped diffusive reaction-coordinate model, the flux contains both potential-driven drift and concentration spreading. High-barrier steady-flux rates depend on diffusion/friction and the shapes of the well and barrier, rather than barrier height alone.
Values and equations
J = -D * (dP/dx + P/(k_B*T) * dU/dx)
- J
- probability current s^-1
- D
- coordinate diffusion coefficient m^2 s^-1
- P
- probability density along length coordinate x m^-1
- x
- reaction coordinate taken as length m
- U
- potential of mean force J
- k_B
- Boltzmann constant J K^-1
- T
- temperature K
Conditions and scope
- A one-dimensional coordinate, approximately equilibrated well and specified friction are approximations; low-friction turnover requires a different regime.
Sources · 1
References
Sources retain their recorded scope. A source link alone does not establish verification of every statement.
Evidence and review
Concepts in Biophysical Chemistry: Kramers theory: Diffusive flux, friction and high-barrier steady-flux rate (relevant textbook section)
2026-10-10 · Bounded author source inspection of diffusive barrier crossing and friction, including the stated conditions; independent branch review is recorded separately.
Entry details
Permanent link to this entry ↗- Record identity
- res-chem-kramers-friction
- Revision
- research.1
- Structured reference record
- Postgraduate & research reference