Differential anomalous-x-ray-scattering study of icosahedral and amorphous Pd58.8U20.6Si20.6

Abstract

The total and differential atomic pair-correlation functions of an icosahedral (quasicrystalline) solid were determined for the first time, directly by the differential anomalous-x-ray-scattering technique using synchrotron radiation. The observed atomic distances involving uranium atoms in icosahedral ${\mathrm{Pd}}_{58.8}$ ${\mathrm{U}}_{20.6}$ ${\mathrm{Si}}_{20.6}$ suggest the presence of a quasicrystalline sublattice with vertex decoration. The pair distribution functions in the icosahedral and amorphous phases are similar up to the second-nearest neighbors, or up to 6 Å.