Einstein equation

https://doi.org/10.1351/goldbook.ET06759
In its most general form, the Einstein equation relates the atomic mobility bi of a species i to the diffusion coefficient Di: i.e., Di=k T bi.
Source:
PAC, 1999, 71, 1307. (Definitions of Terms for Diffusion in the Solid State) on page 1314 [Terms] [Paper]