Diffuse X-Ray Reflexions

Abstract

FOLLOWING the observation by Sir William Bragg that diffuse scattering takes the form which it should have if it were due to diffraction by small groups of atoms within a crystal (as originally suggested by Preston), Prof. G. E. M. Jauncey¹ has obtained a formula giving the resulting positions of the diffuse spots for small values of (i-i_B), i being the glancing angle of incidence on the set of crystal planes for which i_B is the Bragg angle. He expresses astonishment that this formula is identical with those deduced by Zachariasen and by Raman and Kath, each on very different assumptions. Mr. G. D. Preston² has pointed out that this formula is an approximation to the formula given by Faxén in 1923, and stated that the physical interpretation of Faxén's formula is that the surfaces of constant intensity surrounding the Bragg points are spheres. This, however, is again only true when (i-i_B) is small.