The paper reports potassium diffusion measurements performed on gem-quality single-crystal alkali feldspar in the temperature range from 1169 to 1021 K. Natural sanidine from Volkesfeld, Germany was implanted with 43K at the ISOLDE/CERN radioactive ion-beam facility normal to the (001) crystallographic plane. Diffusion coefficients are well described by the Arrhenius equation with an activation energy of 2.4 eV and a pre-exponential factor of 5×10-6m2/s, which is more than three orders of magnitude lower than the 22Na diffusivity in the same feldspar and the same crystallographic direction. State-of-the-art considerations including ionic conductivity data on the same crystal and Monte Carlo simulations of diffusion in random binary alloy structures point to a correlated motion of K and Na through the interstitialcy mechanism.
CITATION STYLE
Hergemöller, F., Wegner, M., Deicher, M., Wolf, H., Brenner, F., Hutter, H., … Stolwijk, N. A. (2017). Potassium self-diffusion in a K-rich single-crystal alkali feldspar. Physics and Chemistry of Minerals, 44(5), 345–351. https://doi.org/10.1007/s00269-016-0862-1
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