M. Fabrizio et al., X-RAY RESONANT SCATTERING AS A DIRECT PROBE OF ORBITAL ORDERING IN TRANSITION-METAL OXIDES, Physical review letters, 80(15), 1998, pp. 3400-3403
X-ray resonant scattering at the K-edge of transition-metal oxides is
shown to measure the orbital order parameter, supposed to accompany ma
gnetic ordering in some cases. Virtual transitions to the 3d orbitals
are quadrupolar in general. In cases with no inversion symmetry, such
as V2O3, treated in detail here, a dipole component enhances the reson
ance. Hence, we argue that the detailed structure of orbital order in
V2O3 is experimentally accessible.