Non-nuclear maxima (NNM), symmetric and asymmetric charge distribution in solar grade Si and n-GaAs, using X-ray powder data

The symmetric and asymmetric charge distribution of bonding electrons in silicon and gallium arsenide has been studied using experimental powder X-ray data sets. The mid-bond electron densities from the origin are found to be 0.787 and 1.725 e/Å3 at 1.175 and 1.222 Å, respectively, for Si and n-GaAs. The effectiveness of powder data sets in precise bonding studies has been verified. Multipole analysis of the valence charge distribution has also been done. The thermal vibration parameters have been studied and presented for both these systems. The magnitudes of the non-nuclear maxima of both these systems are consistent with those obtained using single-crystal studies.