Patterson Fourier analysis of the icosahedral (Al,Si)-Mn alloy

Neutron and absolute x-ray diffraction data obtained from single-phase icosahedral powder ${\mathrm{Al}}_{73}$ ${\mathrm{Mn}}_{21}$ ${\mathrm{Si}}_6$ are analyzed using a generalized Patterson autocorrelation function in three dimensions. The icosahedral pattern is quasiperiodic. The local atomic arrangements match those encountered in the prototypic crystalline α phase. Extra peaks in the local icosahedral pattern match those of an icosahedrally rotated α pattern.