J. Phys. IV France 7 (1997) C2-481-C2-483
Angular-Dependence in the K Pre-Edge XANES of Cubic Crystals : The Separation of the Empty Metal eg and t2g States of NiO and FeOD. Heumann, G. Dräger and S. Bocharov
Fachbereich Physik der Martin-Luther-Universität, 06108 Halle, Germany
It is well known that by applying the angular dependence of the dipole transition matrix elements on the K XANES of single-crystal samples, the different pm-like DOS components (m = x,y,z) of the empty states can be well resolved. Analyzing quadrupole transitions in the pre-edge absorption region allows to fulfill a symmetry resolution of the different dm-states (m = xy ,xz, yz,x2-y2,z2). This has been done for the first time at the cubic single-crystals NiO and FeO, where we could differentiate between eg and t2g components of the empty states using the orientation dependence of the absorption spectra. The Cu K XANES of tetragonal Bi2Sr2CaCU2O8 could be also resolved into the nondegenerated pm- and dm-like components. The method will be demonstrated and results for NiO, FeO and Bi2Sr2CaCU2O8 are presented and discussed.
© EDP Sciences 1997