We have recorded x-ray Raman-scattering spectra from graphite and diamond with high resolution and good signal-to-noise (S/N) ratio by excitation with hard x rays from synchrotron radiation. The scattering spectra show characteristics predicted by the theory. The observed scattering spectrum for graphite was not exactly the same as the absorption spectrum, possibly because of polarization effects in the anisotropic materials. In the case of diamond powder, however, oscillations identical with those found in the extended x-ray-absorption fine structure (EXAFS) spectrum were observed, and from an analysis employing the formula used for EXAFS, interatomic distances were obtained. Thus, it is experimentally confirmed for the first time that x-ray Raman spectroscopy by using hard x rays can supply the same information as the soft-x-ray EXAFS. X-ray Raman spectroscopy can thus be a substitute for EXAFS to determine the local structure around low-atomic-number elements whose EXAFS study is plagued with inherent experimental difficulties.

• Received 29 November 1988

DOI:https://doi.org/10.1103/PhysRevB.39.7590