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The polarization dependence of the DAFS signals

The tensor properties of tex2html_wrap_inline1400 are reflected in the polarization dependence of the DAFS signals. The EDAFS polarization dependence is analogous to that of EXAFS. For single-scattering EXAFS, the polarization dependence is tex2html_wrap_inline1536, where tex2html_wrap_inline1538 specifies the direction from the absorbing atom to the back-scattering neighbor; the analogous dependence for EDAFS is tex2html_wrap_inline1540. For multi-leg single-scattering paths, the EXAFS polarization dependence only depends on the two legs closest to the absorbing atom and is given by tex2html_wrap_inline1542, where tex2html_wrap_inline1544 and tex2html_wrap_inline1546 specify the directions of the two closest legs; the analogous dependence for (nonmagnetic) EDAFS is given by tex2html_wrap_inline1548.

The DANES and XANES polarization dependences are more complicated. The newest FEFF codes calculate the correct polarization dependence of the XANES matrix elements starting a little above threshold, and over the entire EXAFS region. These full FEFF calculations show that the simple polarization dependence tex2html_wrap_inline1542 works very well in the EXAFS region. The full polarization dependent FEFF codes for DANES and EDAFS are currently under development.