Diffuse Scattering of X-Rays from Sylvine—More Exact Measurements

Harvey's $S$ values for sylvine at 295°K agree qualitatively with the theoretical $S$ values calculated from James and Brindley's quantum-mechanical $f$ and $E_{\mathrm{jj}}$ values. Quantitatively, the difference between experiment and theory is too great for comfort. Accordingly, we have made a more exact and careful determination of the experimental $S$ values and have found a remarkable agreement between experiment and theory. This shows the excellence of the present theory of diffuse scattering and the accuracy of the $f$ and $E_{\mathrm{jj}}$ values which James and Brindley have calculated by approximate methods. Our results are not in accord with the idea that the probability distribution is the same for all electrons. Also experiment has shown that turning the crystal plate in its own plane has no effect on the diffuse scattering in a given direction. This indicates that the atoms of sylvine possess spherical symmetry as far as the scattering of x-rays is concerned. Spherical symmetry is assumed in the theory.