  We present the first Raman investigation of icosahedral quasicrystals. Broad
structured bands in the energy range up to ~ 500 $cm^{-1} have been observed in
a series of AlFeCu, AlPdMn and AlPdRe systems. Original information on the
vibrational density of states g(omega) was obtained for AlPdRe; for AlFeCu and
AlPdMn estimated g(omega) shows a good agreement with the previous neutron
results, but demonstrates finer structure. Strong increase in the parameter of
electron-vibrational coupling for the low-energy vibrations and its correlation
with changes in electronic conductivity has been observed in the series from
AlFeCu to AlPdRe. This suggests the increase of the degree of localization for
these vibrational excitations and involved electronic states.
