A method of calculating the integral breadths of Debye-Scherrer lines: generalization to non-cubic crystals

Stokes and Wilson(1,2) have shown that the integral breadths of the Debye-Scherrer lines produced by small or imperfect crystals of the cubic system are given by or, what is the same thing, that the apparent particle sizes are given by In these equations λ is the X-ray wave-length, θ is the Bragg angle, V t is the volume common to the crystal and its ‘ghost’ shifted a distance t in the hkl direction(1), and J t is the mean value of the product FF of the structure amplitudes of two cells separated by a distance t in the hkl direction (2). The purpose of this note is to outline an argument which establishes the same result for crystals of any symmetry.