Sedimentation of atoms in condensed matter: Theory

Abstract

Abstract Self-consistent equations are presented for the sedimentation of atoms or molecules in multicomponent condensed systems under an acceleration field. The theory is constructed on the basis of a mean-field approximation, the linear phenomenological matrix law with an expression of atom fluxes and the Nernst-Einstein relation. Accordingly, the effects of the self-interaction between the solutes, the density change, the chemical activity, etc., were consistently taken into account. For two- and three-component systems, the diffusion equations were rewritten in simple useful forms. The theory can immediately be used in the conventional ultracentrifuge as used in biochemistry. A numerical analysis at equilibrium of the sedimentation of atoms induced by a centrifugal field was performed for two- and three-component systems, and the final distributions of concentrations and density were given via the external energy under several atomic and chemical conditions in a wide external energy region. The effect...