X-Ray to Visible Wavelength Ratios

Defect structure dependence on composition in lithium niobate

“…The linewidths of the 30.0, 33.0 and 00.12 profiles ranged between 85 and 635 arc". The resulting a-or c-lattice constant at each point on a plate, corrected to 298 K by the expansion coefficients for well characterized material (Gallagher & O'Br~,an, 1985), was based on A(Cr Kay) = 2.28970 A (International Tables for X-ray Crystallography, 1974) for the 30.0 and 00.12 and A(Cu Kant) ---1.540598 A (Deslattes & Henins, 1973) for the 33.0 reflections. The standard deviation in each lattice-constant measurement was estimated by three methods: an internal estimate based on differences among replications, an external estimate based on the difference between the midpoint at half height and the centroid of the profile, and a third estimate based on differences among the final lattice-constant magnitudes assuming crystalline homogeneity.…”

“…A group of 25 reflections with 22.2-< 0-< 45.7 ° was measured on both crystals with Mo Ka radiation [;t(Ka~.2)= 0.709319, 0.713609 /~ (Deslattes & Henins, 1973)] from a graphite monochromator. Values of 20(hkl)= to (hkl) -to (hkl), with to (hkl) determined at negative 20 angle in the bisecting mode, were used to obtain the lattice constants at 298 K in Table 1 by the method of least squares.…”

A silicon powder diffraction standard reference material

“…One crystal was of the SRM material. The second was obtained from a sample related to the X-ray laser interferometer measurements of Deslattes & Henins (1973). One end of a crystal was glued to a glass capillary, and the crystal was positioned such that the (111) surface near the other end was used for measurements.…”

“…Moreover, the dz2o interplanar spacing (and hence a) has been determined relative to the wavelength of a He-Ne stabilized laser to better than 1 p.p.m, in a redetermination of X-ray wavelengths on an absolute scale (Deslattes & Henins, 1973). A number of other precision relative latticeparameter determinations, that is a/2, have also been reported in the literature and can be used for comparison.…”

“…A number of other precision relative latticeparameter determinations, that is a/2, have also been reported in the literature and can be used for comparison. For the purpose of this paper, values of a/2 have been converted to values of a with 2(Cu Ke~ peak) taken as 1.5405981 A (Deslattes & Henins, 1973). …”