ELECTRONIC DISTRIBUTIONS AND LOCAL RANGE ORDER IN CRYSTALS AND QUASI-CRYSTALS

The Al 3p distribution, obtained using the soft X-ray emission spectro scopy technique, is analyzed for various Al-Mn and Al-Cu-Fe alloys, cr ystalline as well as quasicrystalline. By comparison with partial dens ities of states' calculations for the various Al sites in the crystall ine phases, the differences that are observed are ascribed to differen ces in Al site occupancy from one alloy to another. For the quasicryst alline icosahedral Al-Cu-Fe alloy, many of the Al atoms could be in si tes comparable to sites in crystalline Al7Cu2Fe to which correspond sh ort Al-Fe distances and no Cu first neighbours. Al-Mg-Pd quasicrystals are examined in two structural states for which the AI-Pd interaction strongly differs. It is suggested that Pd atoms could be closer to Al in one structure with respect to the other.