title: Temperature diffuse scattering of nanocrystals.
abstract: The effects of thermal vibrations on X-ray powder diffraction patterns are discussed. Special considerations for extremely small crystallites are described, including the occurrence of surface and edge vibrational modes, and a restriction on the maximum phonon wavelength. In doing so, a complete temperature diffuse scattering (TDS) model is presented, which includes the influence of these features on: the Debye-Waller parameter; first-order TDS; and higher-order TDS terms. The importance of using an accurate TDS representation is studied as a function of temperature and crystallite size. It is found that a misrepresentation of the TDS for small crystallites can lead to an error in the determined Debye-Waller parameter on the order of 20-40% and a slight overestimation of the peak broadening. While the presented theory is primarily developed considering X-ray scattering, the same expressions are expected to describe the TDS in faster-than-sound neutron powder diffraction measurements.
authors.affiliation: Materials Science and Engineering Department, Georgia Institute of Technology, Atlanta, GA, USA. kbeyerlein3@gatech.edu
authors.forename: K R
authors.initials: KR
authors.lastname: Beyerlein
authors.forename: M
authors.initials: M
authors.lastname: Leoni
authors.forename: P
authors.initials: P
authors.lastname: Scardi