Thermal Vibrations of Atoms in Cubic Crystals I. The Temperature Variation of Thermal Diffuse Scattering of X-rays by Lead Single Crystals

The intensity of thermal diffuse scattering of x-rays which normally increases with rise of temperature is expected to decrease with temperature increase for scattering near to high order reciprocal lattice points for crystals of low Debye characteristic temperature. Observations on lead single crystals agree well with theory. This decrease of diffuse scattering occurs when short thermal wavelengths are becoming predominant in the lattice, and so should be related to the melting point. A relationship between the Debye characteristic temperature and the melting point is obtained which has also been derived by Lindemann from other considerations.