Width of Debye-Scherrer lines for finite spectral width of primary beam
"The width of a Debye-Scherrer line under the combined influence of spectral width of the primary radiation and of the small size of the crystal grains is calculated, omitting all geometric causes of line broadening. The shape of the crystals is assumed spherical, with the same diameter for all grains. The orientation is assumed to be random, with negligible statistical fluctuations" (p. 1).
Abstract In the present study we calculated the electronic structure of the valence skipping compound SnF 3 and BaBiO 3 from first-principles. We confirmed that the charge-density-wave (CDW) is formed in SnF 3 , and the Sn atoms in two crystallographic different sites take the valence Sn 2+ and Sn 4+ . Structure optimization study reveals that this CDW is stable, though the atomic position is slightly different from the experimental data. This behavior is in contrast with the case of BaBiO 3 , where the structure optimization leads to the uniform state, which means that two Bi sites are equivalent. The CDW state is hard in SnF 3 , which means that the CDW gap is large enough and it is difficult to melt this CDW order.