J. Phys. IV France 7 (1997) C2-107-C2-110
Pre-Edge Fine Structure (PEFS) of the K-XAS for the 3d Atoms in Compounds: A New Tool for Quantitative Atomic Structure DeterminationR.V. Vedrinskii1, V.L. Kraizman1, A.A. Novakovich1, Ph.V. Demekhin1, S.V. Urazhdin1, B. Ravel2 and E.A. Stern2
1 Dept. of Physics, Rostov State ; University, 5 Zorge Str., Rostov-on-Don, 344090, Russia
2 University of Washington, Seattle WA981195, USA.
The two mechanisms are shown to be mainly responsible for the formation of the K-XAS PEFS for the 3d-atoms in the compounds: p-d mixture (PDM) which makes allowed the ls-electron transitions to the absorbing atom 3d-states influenced by the screened hole potential and the ls-electron transitions to the unoccupied 3d-states of the neighbouring atoms. The intensities of the PDM induced peaks strongly depend on the displacement of the absorbing atom from the center of inversion symmetry and on the X-ray polarization vector e direction. Taking into account this dependence and employing the experimental Ti K-XAS for the PbTi03 monocrystal measured for different temperatures and directions of the vector e the ferroelectric phase transition in this crystal has been studied.
© EDP Sciences 1997