Extended x-ray-absorption fine structure: Direct comparison of absorption and electron yield

Publisher Website
Google Scholar
Abstract
Using a simple ionization detector to monitor the total electron yield, we have measured extended x-ray-absorption fine structure above the Ni, Fe, and Cr K edges in the x-ray region. This technique is somewhat surface sensitive; we estimate a sampling depth of about 1000 Å. The fact that these materials do not differ from the bulk over this depth allows direct comparison with conventional absorption measurements. We find that interatomic spacings determined from the yield agree well with those measured by absorption. However, amplitudes differ significantly. These results have implications for the extraction of coordination numbers from the surface-sensitive variants of extended fine structure which monitor the electron yield. Finally, the electron-yield detector used here, employing conventional x-ray monochromators and not requiring elaborate precautions to prepare pristine surfaces, should prove useful in the study of, e.g., plated specimens or catalysts.