The Lamm equation can be written:

where c is the solute concentration, t and r are the time and radius, and the parameters D, s, and $omega$ represent the solute diffusion constant, sedimentation coefficient and the rotor angular velocity, respectively. The first and second terms on the right-hand side of the Lamm equation are proportional to D and $somega^\{2\}$, respectively, and describe the competing processes of diffusion and sedimentation. Whereas sedimentation seeks to concentrate the solute near the outer radius of the cell, diffusion seeks to equalize the solute concentration throughout the cell. The diffusion constant D can be estimated from the hydrodynamic radius and shape of the solute, whereas the buoyant mass $m\_\{b\}$ can be determined from the ratio of s and D

Solute molecules cannot pass through the inner and outer walls of the cell, resulting in the boundary conditions on the Lamm equation

Derivation of the Lamm equation

Faxén solution (no boundaries, no diffusion)

References and notes