Bjerrum length
The Bjerrum length (after Danish chemist Niels Bjerrum 1879–1958 ) is the separation at which the electrostatic interaction between two elementary charges is comparable in magnitude to the thermal energy scale, k B T {\displaystyle k_{\text{B}}T} , where k B {\displaystyle k_{\text{B}}} is the Boltzmann constant and T {\displaystyle T} is the absolute temperature in kelvins. This length scale arises naturally in discussions of electrostatic, electrodynamic and electrokinetic phenomena in electrolytes, polyelectrolytes and colloidal dispersions.