ELECTRON-DENSITY DISTRIBUTION IN GERMANIUM FROM X-RAY-POWDER DATA BY THE MAXIMUM-ENTROPY METHOD

The electron density distribution map of germanium has been drawn usin g the maximum-entropy method (MEM) with 11 independent structure facto rs and one combined structure factor, which were determined by the pow der pattern decomposition from X-ray data. The R factor was 0.5% for t he final MEM density map, though we used the powder data. The result i ndicates that the bonding electron with a level of 0.3 e angstrom-3 is clearly visible in the map even though no forbidden reflection is inc luded in the analysis. This is the first observation of the bonding el ectron from powder X-ray diffraction data. Both the observed and calcu lated structure factors agreed well with previous measurements, where available. The structure factor F(222)e(-M) for the 222 forbidden refl ection at room temperature calculated from the maximum-entropy map is - 1.056 and it shows good agreement with those measured by the integra ted intensity using a nearly perfect single crystal.