An important aspect of high-
superconductor research is the connection
between the hole concentration in the 
-
bands, the
Cu valence, and the of the material. In the
high- superconductors, the Cu(2) bond
valence sum has been shown [29] to have the same shape versus
as , while the bond valence sum of the Cu(1) chain
atoms has a linear dependence on oxygen content and is independent of the
material's superconductivity. Polarized XANES measurements have been very
useful in studies of new high- materials. For example, the 3d
valence electronic configuration of the Cu atoms in was determined by comparing the XANES features of
to XANES fingerprints of closely related
Cu-O compounds [32]. Since DANES methods provide precise,
and very easy, assignments of near-edge features to specific sites, DANES
studies should prove useful in site-specific valence determinations of
high- and other materials. In addition, because the tensor properties
of the DANES signals are sensitive to the empty orbital symmetries and
occupations, there is considerable interest in applying tensor DANES to
make site-specific empty orbital maps [34].