Anisotropy of Resonant Inelastic X-Ray Scattering at the K Edge of Si:Theoretical Analysis

We investigate theoretically the resonant inelastic x-ray scattering (RIXS) at the $K$ edge of Si on the basis of an ab initio calculation. We calculate the RIXS spectra with systematically varying transfered-momenta, incident-photon energy and incident-photon polarization. We confirm the anisotropy of the experimental spectra by Y. Ma {\it et al}. (Phys. Rev. Lett. 74, 478 (1995)), providing a quantitative explanation of the spectra.Comment: 18 pages, 11 figure

Non-normalization behavior of crystal glitches in an EXAFS spectrum: Is it possible to remove crystal glitches?

The existence of crystal glitches in EXAFS data is widely recognized and is usually dealt with during data analysis. However, in many cases, especially as samples become more dilute, the disruption of the data can become irretrievable. The advent of new, high output, double-crystal x-ray monochromators has made it necessary to investigate the cause of such glitches with a view to reducing them in the original data. The occurrence of multiple reflections within the crystal gives rise to the glitches seen in EXAFS data when the two crystals in a double-crystal monochromator are not accurately aligned. The results of a simple alignment of such a double-crystal monochromator are presented and show a reduction of the glitches in the recorded data. A purpose-built monochromator for further investigation of this problem is described and some results towards the further reduction of glitches are presented. It is shown that the removal of crystal glitches from EXAFS data is possibl