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This article in SSSAJ

  1. Vol. 37 No. 4, p. 548-552
    Received: Jan 1, 1973
    Accepted: Mar 6, 1973

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Computer Procedure for Calculating Counter-Diffusion Coefficients1

  1. B. D. Fuqua,
  2. J. E. Dunn and
  3. D. A. Brown2



A procedure for computer calculation of counter-diffusion coefficients has been combined with the quick-freeze technique to measure counter-diffusion of ions. Two separate programs were employed to evaluate the counter-diffusion coefficients at 0.1-cm increments along the diffusion axis. Subroutines were available in the programs for plotting the ion distribution curve and the relationships of counter-diffusion coefficients versus diffusion distance and counter-diffusion coefficients versus relative concentration. Examples of Sr2+ diffusing against H+ and Na+ diffusing against H+ are presented to illustrate the potentialities for computer calculation and plotting of significant diffusion parameters. The diffusion coefficients of both Sr2+ and Na+ varied with changes in the ionic concentrations indicative of counter-diffusion processes. The counter-diffusion coefficients determined by the computer procedure were essentially the same as the values calculated by the graphical method. The computer procedure is an accurate and rapid method for calculating diffusion coefficients which are dependent on concentration and is adaptable to both single and multi-ion systems.

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