RESONANT RAMAN SCATTERING: SPECTROSCOPY AND CRYSTALLOGRAPHY. C. J. Sparks, G. E. Ice, Oak Ridge National Laboratory, Oak Ridge, TN 37831-6118, USA

Resonant Raman scattering which occurs near absorption edges can be both a useful spectroscopy of the chemical state and a background nuisance in the measurement of weak diffuse scattering. This resonant inelastic scattering arises from the promotion of a bound electron into an unfilled bound state and is a measure of the unfilled density of states in the presence of a core hole. Some applications of this new spectroscopy will be reviewed and compared with other spectroscopies. This resonant radiation emission has a nonradiative counterpart in Auger electron emission which is also developing into a useful spectroscopy. Those interested in the measurement of diffusely distributed intensity associated with liquids, amorphous solids, short-range order and defects need be aware of this inelastic scattering contribution to your signal; Resonant Raman scattering is most intense when the incident radiation is just below the absorption threshold to maximize elemental contrast with the resonant (dispersion) terms of the x-ray atomic scattering factor. The magnitude of resonant Raman scattering will be illustrated by comparing its cross section to the cross section for Compton and elastic scattering. Means to deal with the inelastic scattering are described.

Research sponsored by the Division of Materials Sciences, U.S. Department of Energy under contract DE-AC05-96OR22464 with Lockheed Martin Energy Research Corporation.