Dispersionskorrektur Δf′ für Nickel nahe derK-absorptionskante

Abstract

Employing an X-ray interferometer the dispersion correction Δf′ of the forward atomic scattering amplitude$f = z + \Delta f' + \Delta f''$ of Nickel is measured using CuK $\bar \alpha$-radiation. Since$\lambda _{CuK\bar \alpha } /\lambda _{K - edge Ni} = 1.037 \approx 1$ a value of Δf′ close to theK-absorption edge is obtained. The result

$$\Delta f\prime = - 1.45 \pm 7.6\% $$

is compared with experimental values by Doan, Kiessing and Lameris and Prins and also theoretical values by Hönl, Dauben and Templeton and Cromer. The present value is considerably smaller than all theoretical estimates.

It is the most accurate value measured so far and-except for the value measured by Kiessing-aggrees with the other experimental values within their (comparatively large) error limits.