Theoretical structure factors for selected oxides and their effects in high-resolution electron-microscope (HREM) images

Abstract

A reasonably detailed analysis of the effects of charge redistribution on both X-ray and electron structure factors as well as for high-resolution electron-microscope images are presented for a series of light-element oxides. The charge redistribution leads to differences of 2-3% for the X-ray structure factors and 5-7% for electron structure factors in the 0-0.5 A(-1) region. There are detectable changes in images of about 10% of the contrast, somewhat dependent upon the alignment of atom columns, specimen thickness and defocus. These studies suggest that charge redistribution may be detectable using a Cc-limited aberration-corrected microscope with a specimen thickness of about 50 A.