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Information content of DAFS compared to XAFS

Because the DAFS and XAFS signals have limited photoelectron wavenumber ``bandwidths'', their information content is limited. The number of independent XAFS points is given by tex2html_wrap_inline1710, where tex2html_wrap_inline1712 is the filtering window width in R-space and tex2html_wrap_inline1716 is the window width in K-space [24]. For typical values, tex2html_wrap_inline1720Å and tex2html_wrap_inline1722, the number of independent points is approximately 10. This is the maximum number of parameters that can be determined from single shell XAFS data. Note, however, that if there are m inequivalent sites, a set of DAFS measurements for m or more inequivalent reflections can provide up to m times as much information as XAFS. If there are also p components in the sample, and each component has m inequivalent sites, then a total of (pmN) parameters can be determined per shell.