Dear all, Thank you very much for your information.
I think the one I am using is Si[111]. It was used for checking the linearity of the diffractometer. I just curious to see some rietveld refinement can be practised myself. I got R-factor (R(F2)) ca. 15% and the simulated PXRD from Si structure is not well matched w the experimental one especially for [111] reflection, it is stronger than the calcuated intensity. [200] is relatively weaker than the expected as well. regards stephen
