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 using the maximum-entropy method (MEM) with 11 independent structure factors and one combined structure factor, which were determined by the powder pattern decomposition from X-ray data. The R factor was 0.5% for the final MEM density map, though we used the powder data. The result indicates 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 included in the analysis. This is the first observation of the bonding electron from powder X-ray diffraction data. Both the observed and calculated structure factors agreed well with previous measurements, where available. The structure factor F(222)e(-M) for the 222 forbidden reflection at room temperature calculated from the maximum-entropy map is - 1.056 and it shows good agreement with those measured by the integrated intensity using a nearly perfect single crystal.