SITE-SPECIFIC EXTINCTION RULE FOR KIKUCHI BANDS IN X-RAY PHOTOELECTRON DIFFRACTION

The anomalous extinction of specific Kikuchi bands has been recently o bserved in the X-ray photoelectron diffraction (XPED) pattern for F1s emission from a CaF2(111) surface; even though the corresponding struc ture factors are not zero. To explain this phenomenon, we have derived a novel extinction rule and have shown that the extinction of Kikuchi bands in XPED depends not only on the structure factors but also on t he lattice sites of source atoms. This rule can be used to locate the lattice sites of impurities in single-crystal substrates.