A New Interpretation of EXAFS Spectra in Real Space. I. General Formalism

Abstract

I. General Formalism BY Yu. A. BABANOV (a), V. V. VASIN (b), A. L. AGEEV (b), and N. V. ERSHOV (a)It is shown that the problem of determining the function of radial atomic distribution around an absorbing atom by oscillations of the X-ray absorption coefficient belongs to a family of incorrect problems. A regularization algorithm is proposed for the problem concerned. Computational schemes realized involving the use of computers are described. Some results of model calculations are given.Es wird gezeigt, daB das Problem der Bestimmung der radialen atomaren Verteilungsfunktion urn ein absorbierendes Atom durch Oszillationen des Rontgenabsorptionskoeffizienten zur Familie der inkorrekten Probleme gehort. Ein Regulierungsalgorithmus wird fur das betrachtete Problem vorgeschlagen. Realisierte Berechnungsschemata, die die Benutzung von Computern einschlielen, werden beschrieben. Einige Ergebnisse von Modellberechnungen werden mitgeteilt.

Overlapping XAFS L Spectra of 3d Metals A New Application of the Regularization Method

“…Applying the regularization method described [2][3][4], one can find the solutions which are shown on Fig. 3.…”

“…2). EXAFS measurements in transmission mode. The extraction of the (k) functions from raw data was used [3,4]. TEY (k) functions were rather noisy due to low statistics so these curves were smoothed.…”

“…For L spectra it is possible to use the regularization method without any modification. Details of solving the EXAFS ill-posed problem may be found in [2][3][4]. For multicomponent systems the theory is easy to generalize.…”

“…FEFF8 simulation of L spectra (the total one (solid line) and the separate contributions: L 3 (dash line), L 2 (dot line) and L 1 (dash dot line)) for pure Fe. [3,4]. Recently a special procedure of deconvolution L 2 -, L 3 -contributions [5] was used for obtaining local structure information.…”

Observation of anharmonicity for copper thin film near room temperatures

“…In this study, the regularization algorithm (Yang & Bunker, 1996, Babanov et al, 1981 has been introduced into the measurement of the anharmonicity. A unnormalized pair distribution is directly obtained by the regularization procedure from the EXAFS spectrum, and the anharmonicity is shown by the asymmetry of the distribution.…”