We report on a systematic study of the unoccupied electronic states of long-range-ordered orthorhombic ${\mathrm{MoNi}}_3$ alloy as well as its parent metals as reference. Measurements included the bremsstrahlung isochromat spectra for incoming-electron kinetic energy of 5414 eV and K-edge x-ray-absorption spectra of Ni. Further, all measured spectra were calculated on the basis of ab initio band-structure calculations performed for the investigated materials. The influence of the core hole on the Ni K-edge absorption spectrum was found to be small. A substantial deviation of the local structure in the long-range-ordered alloy was inferred by analogy to a local deformation of the lattice in semiconducting pseudobinary (ternary) alloys.

• Received 6 May 1991

DOI:https://doi.org/10.1103/PhysRevB.45.1581