ANALYSIS OF DAFS FINE-STRUCTURE AND BACKGROUND

The oscillatory structure in the diffraction anomalous fine structure (DAFS) spectrum contains at least as much local structural information as X-ray absorption fine structure (XAFS). We present three XAFS anal ysis programs, ATOMS, AUTOBK, and FEFFIT, which are easily extended to background removal and fine structure analysis in DAFS. The backgroun d subtraction and curve-fitting of DAFS data require the crystallograp hic structure factor, F, for the material. ATOMS calculates F for an a rbitrary crystal from tables of anomalous scattering factors. AUTOBK, an automated background removal program, estimates the shape of the DA FS background and correctly normalizes the resulting chi(k) FEFFIT, an XAFS curve-fitting program using multiple scattering theory and sophi sticated model-building capabilities, is easily extended to handle the DAFS oscillatory structure. We show the success of these programs in handling DAFS spectra.