Charge density distribution of the parent phase of a Cu-Al-Ni alloy by the maximum entropy method

The charge density distribution of the D0(3)-type parent phase of a Cu-13.5A1-4.1Ni (mass%) alloy was obtained from synchrotron powder diffraction data by the maximum entropy method (MEM). In the MEM charge density map, overlapped electron densities were found between the first nearest neighbor atoms, indicating the existence of covalent bonds between Cu(1) and Cu(2) atoms and Al and Cu(2) atoms. The covalent bond was rather weaker between the unlike atoms than between the like atoms. The covalent bond between the first nearest neighbor atoms is supposed to be due the hybridization of the atomic orbitals.