On the contribution of thermal diffuse X-ray scattering to the integrated Bragg intensities of single crystals

The effect of including first-order and second-order thermal diffuse scattering contributions on the theoretical treatment for integrated Bragg intensities of single crystals is given for crystals belonging to any crystal system and with any number of atoms per unit cell. With certain restricting approximations and assumptions, the modified integrated intensity is found to be a product of the Bragg scattering and a factor, exp (C sin² θ₀/λ²), where C is a simple function of the X-ray wavelength, the temperature, the angular peak-width, and a quantity related to the elastic properties of the crystal. For cubic crystals, C is found to be approximately constant and thus confirms the result obtained by Nilsson (1957, Ark. Fys. 12, 247) for simple cubic crystals. The theory is applied to Al and KCl crystals, and calculated values for the ratio of uncorrected to corrected integrated Bragg intensities show reasonable agreement with some experimental values obtained using the Mössbauer effect.