Information stored in high-Q space: Role of high energy scattering

Much of crystallographic diffraction measurements are focused on obtaining information with Q(=4πsinθ/λ) below 17 Angstrom -1 or d>0.35 Angstrom, with the implicit assumption that no useful information is stored in the Q space above. However, this assumption is valid only with respect to the periodic lattice structure. Actually, high-Q space is full of information on the local atomic structure that could be of major importance in some cases. We discuss high energy x-ray or neutron scattering as the methods of obtaining the data from the high-Q space, and the atomic pair-distribution function (PDF) analysis as the means of extracting information from such data. Preliminary data of our recent high-energy x-ray scattering measurement on a MX compound are shown for which this type of analysis is likely to play a significant role in understanding the properties. copyright 1997 American Institute of Physics