The determination of layer charge by curve-fitting of Lorentz- and polarization-corrected X-ray diagrams

Abstract

The clay fraction from the B horizon of a Psammentic Hapludalf containing vermiculite and smectite was treated with n-alkylammonium chloride ranging from n_c = 6 to n_c = 16. X-ray data were obtained by step-scanning, stored in a computer, corrected with the Lorentz and polarization factors and then fitted with a deconvolution programme. The layer charge was determined from the uncorrected, the corrected and the fitted diagrams, respectively. The evaluated confidence limits of ξ decreased in the same order revealing the vermiculite to be a high-charge type. The computed charge distribution of the smectite changed from an unlikely bimodal to a nearly symmetrical distribution.