Effect of non-hydrostatic stress on X-ray diffraction in a diamond anvil cell （DAC） is studied. The pressure gradient in the sample chamber leads to the broadening of the diffraction peaks, which increase with the hkl index of the crystal. It is found that the difference between the determined d-spacing compressive ratio d/do and the real d-spacing compressive ratio dr/do is determined by the yield stress of the pressure transmitting media （if used） and the shear modulus of the sample. On the basis of the corrected experiment data of Mao et al. （MXB86）, which was used to calibrate the most widely used ruby fluorescence scale, a new relationship of ruby fluorescence pressure scale is corrected, i.e., P = （1904/9.827）[（1 ＋ △λ/λ0）9.827 - 1].
We propose an efficient implementation of combining dynamical mean field theory（DMFT） with electronic structural calculation based on the local density approximation（LDA）.The pseudo-potential-plane-wave method is used in the LDA part,which enables it to be applied to large systems.The full loop self consistency of the charge density has been reached in our implementation,which allows us to compute the total energy related properties.The procedure of LDA＋DMFT is introduced in detail with a complete flow chart.We have also applied our code to study the electronic structure of several typical strong correlated materials,including cerium,americium and NiO.Our results fit quite well with both the experimental data and previous studies.
