IS THE AL-PD-MN ICOSAHEDRAL PHASE CENTROSYMMETRICAL

The possible non-centric character of the icosahedral Al-Pd-Mn phase h as been checked by measuring Bijvoet pairs above the Pd K edge on a si ngle grain. The integrated intensity of HKL and -H -K -L reflections i s found to be identical within the experimental errors. The computed i ntensity variation for 45-degrees phase differences are computed to be much larger than the observed values. This indicates that the icosahe dral phase is centrosymmetrical or presents phases very close to 0 or pi.