On charge density determinations in intermetallics by quantitative convergent beam electron diffraction

Abstract

Experimental measurements of the charge distribution in intermetallics would be both a useful confirmation of calculated charge density maps and a great aid in explaining the inherent brittleness of many intermetallics, especially the cubic trialuminides. Bonding charge densities were previously measured in GaAs by a convergent beam electron diffraction (CBED) technique in a transmission electron microscope operated at 100 kV. By electronically recording an energy filtered CBED pattern and comparing this measured rocking curve to a calculated one, an accurate electron scattering factor of the crystal can be determined. While the technique utilizes readily available equipment, a number of experimental difficulties remain.