Arcs of diffuse scattering from icosahedral Ti—Mn quasicrystals

In diffraction from some icosahedral quasicrystals, diffuse scattering is concentrated on finite geometrical loci in reciprocal space. This diffuse scattering typically appears as arcs in transmission electron microscopy diffraction patterns. The new Ti—Mn icosahedral phase produces much more intense arcs than previously observed in quasicrystals, allowing a significantly deeper study of them. In this paper, we present a detailed description of these arcs. Two existing theoretical models, transition-state theory and the icosahedral glass, predict arcs in qualitative agreement with the observations but disagree with the details of their observed shapes and positions.