diffusion coefficientmedical dictionary

For the translational diffusion of solutes, diffusion is described by Fick's First Law, that states that the amount of a substance crossing a given area is proportional to the spatial gradient of concentration and the diffusion constant (D), that is related to molecular size and shape. A useful derived relationship is that the mean square distance moved by molecules in time t is 6Dt.

This entry appears with permission from the Dictionary of Cell and Molecular Biology

(11 Mar 2008)