Recent AFM variants form images on the basis of the frequency shift, phase shift, or amplitude attenuation of an oscillating tip due to interactions with the surface. The view at the atomic scale SPM provides one of the few ways in which UHV and in situ observations can be directly linked. Such work is helping to confirm the validity of atomic structures assumed in surface chemistry models. Surface structure, defects, and oxidation-reduction at the atomic scale can be studied using SPM techniques. The cells are marked, and the edge length in both views is 0.5 nm.
All images are in false color.
Copyright 1996 by the American Physical Society. The technique also provides information on the presence or lack of surface disorder as well as the distribution of structured and defective areas. Structural defects are often sites of preferential adsorption, dissolution, or catalytic activity on mineral surfaces that are otherwise relatively unreactive. At an atomic scale, steps and kinks are discernible. These are sites of molecular attachment and detachment during crystal growth or dissolution, a process that can be key to partitioning of pollutants such as heavy metals between solid and solution.