Open AccessThe Stokes-Einstein law for diffusion in solution
Author(s) -
Christina C. Miller
Publication year - 1924
Publication title -
proceedings of the royal society of london. series a, containing papers of a mathematical and physical character
Language(s) - English
Resource type - Journals
eISSN - 2053-9150
pISSN - 0950-1207
DOI - 10.1098/rspa.1924.0100
Subject(s) - avogadro constant , fick's laws of diffusion , einstein relation , diffusion , constant (computer programming) , einstein , thermodynamics , physics , molecule , kinetic energy , mathematical physics , classical mechanics , quantum mechanics , metric (unit) , operations management , computer science , economics , programming language
Einstein has shown that the relation between molecular movement and diffusion in a liquid may be expressed by the following equation, when the particles move independently of each other:— D=͞Δ2 /2t , (1) D being the diffusion constant and ͞Δ2 the mean square of the deviation in a given direction in timet . Further, if it be assumed that the particles possess the same mean kinetic energy as gas molecules at the same temperature, the following equation holds ͞Δ = 2RT/N .t /C (2) where R is the gas constant, N Avogadro’s number, T the absolute temperature, and C a constant, which we might call the frictional resistance of the molecule. Hence, D = RT/N .1/C. (3) Under the foregoing assumptions equations (2) and (3) hold equally well for dissolved molecules and particles of greater dimensions.