International
Tables for Crystallography Volume C Mathematical, physical and chemical tables Edited by E. Prince © International Union of Crystallography 2006 
International Tables for Crystallography (2006). Vol. C, ch. 6.2, p. 596
Section 6.2.1. Expressions for intensity of diffraction 
The expressions for the intensity of diffraction of Xrays contain several trigonometrical factors. The earlier series of International Tables (Kasper & Lonsdale, 1959, 1972) gave extensive tables of these functions, but such tables are now unnecessary, as the functions are easily computed. In fact, many crystallographers can ignore the trigonometric factors entirely, as they are built into `blackbox' dataprocessing programs. The formulae for singlecrystal reflections (b) and (c) of Table 6.2.1.1 in the previous edition (Lipson & Langford, 1998) list only the integrated reflection power ratio (i.e. integrated reflection) under the strong absorption case. The revised formulae given here include both the reflection power ratio and the integrated reflection power ratio for a crystal slab of finite thickness with any values of the ratio of the absorption to the diffraction cross sections and under all possible kinds of diffraction geometry.

A conspectus of the expressions for the intensity of diffraction as recorded by various techniques, including the fundamental constants as well as the trigonometric factors, is given in Table 6.2.1.1. Details of the techniques are given elsewhere in this volume (Chapters 2.1 – 2.3 ) and in textbooks, such as those of Arndt & Willis (1966) for singlecrystal diffractometry and Klug & Alexander (1974) for powder techniques. Notes on individual factors follow.
References
Arndt, U. W. & Willis, B. T. M. (1966). Single crystal diffractometry. Cambridge University Press.Kasper, J. S. & Lonsdale, K. (1959). International tables for Xray crystallography. Vol. II. Mathematical tables. Birmingham: Kynoch Press.
Kasper, J. S. & Lonsdale, K. (1972). International tables for Xray crystallography. Vol. II. Mathematical tables. Corrected reprint. Birmingham: Kynoch Press.
Klug, H. P. & Alexander, L. E. (1974). Xray procedures for polycrystalline and amorphous materials. New York: John Wiley.