The electronic structure of the 3d transition metals

The measurements and calculations of the charge, spin and momentum density of the metallic elements Ti to Ni are examined. Both the Compton profiles (momentum density) and X-ray scattering factors (charge density) are shown to provide a direct determination of the cohesive energy. It generally appears that the 3d spin density is contracted relative to the free atom while the 3d charge density builds up at the Wigner–Seitz cell boundary relative to the free atom particularly near the bottom of the band. No theoretical calculation is available which evaluates charge, spin and momentum density as well as cohesive energy. In addition, a significant disparity between theory and experiment exists for the momentum and charge density anisotropies in the b.c.c. metals. Suggested areas for further work are given.