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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.

The errors in the initial EXAFS data are simulated numerically. The comparative sensitivity of the regular methods and of the Fourier transformation method to these errors is analyzed. The theoretically calculated normalized oscillating part of the absorption coefficient X(k) for polycrystalline copper a t T = 77.4 K is compared with the experimental spectrum obtained with the use of a synchrotron facility. The spectrum involved is processed using regular methods.

Generalizing the regular solution algorithm the inverse problem of Mossbauer spectroscopy is proposed for obtaining the distribution function of the hyperfine interaction parameters from the spectrum. By model calculations it is shown that the algorithm is stable with respect to statistical noise and errors in the spectrum parameters. It is noticed that the algorithm is applicable strictly only to objects which properties can be described by a continuous distribution of one of the hyperfine interaction parameters. The condition of the normalization is introduced as an additional criterion of the correctness of the solution. There is a possibility of investigating the spectra with paramagnetic components. The algorithm may be applied to an analysis of both, poorly resolved and well resolved spectra. npemomeH 0604embIji perynnpHbIji ~O P H T M peluemn 06paTHOfi sanaqu MeCC6ay3pOB3KO6 CIIeKTpOCKOIIHH AJIUIII IIOJIy9eHm I$yHKqEIU PaCIIpeneJIeHUR IIapaMeTpOB CBepXTOHKOrO B3aUMOAefiCTBHX U3 CneKTpa. Ha MOneJIbJibIX paCWTZlX nOKa3IW0, 9TO WrOpHTM YCTOkIUB IIO OTHOIIIeHHH) K &iTOp€iTM CTpOrO IIpHMeHHM Nub K 06%eKTaM, CBOkTBa KOTOPbIX MOrYT 6bITb OIIECaHbI He-YCJIOBHe HOPMWPOBKH KBK nOlIOJIHuTenb& KpIlTepd KOppeKTHOCTH PeIIIeHUX. kiMeeTCR B03MOX-HOCTb UCCJEnOBaHUII CIIeKTpOB C IlapaMarHuTHbIMIl COCTaBJIXIOIIpiMH. AnropuTM MOXHO npuMeHIlTb cTaTucTuqecKoii norpemaocni w K o r u u 6 r a~ B onpenenearn napaMeTpoe cnempa. 3 a~e q e~0 , w o I I~~P~I B H~I M pacnpeneneJiweM o p o r o ~3 napaMeTpoB csepxTomoro ~s a w l o n e i i c~~w a . BBeneHO a~anu3a K a K cna60pa3peme~1mx TaK H xop0111opa3peme~m1x cnex-ipoB. ') Kirov street 132, SU-426OOO Izhevsk, USSR.

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