Experimental investigation of the atomic dynamics of amorphous and icosahedral alloys

Most recent results from the experimental investigation of the single particle dynamics and the collective atomic motions in amorphous metals and in icosahedral alloys using neutron inelastic scattering techniques are briefly presented. The extension of the dispersion curve of short wavelength collective motions into the first pseudo Brillouin zone by neutron Brillouin scattering and the investigation of crystal field excitations in an amorphous metal and its dependence on structural relaxation are discussed. Comparative studies of the atomic dynamics of polydomain icosahedral alloys, approximant polycrystals, and polycrystals with similar chemical composition but different structure are discussed. It is shown that the generalized vibrational density of states and the total dynamic structure factor of the icosahedral alloys investigated so far are rather different from any crystalline sample except for the case of higher order approximants with very large units cells.