Compton scattering studies of electron correlation effects in chromium

The (100), (110) and (111) direction Compton profiles of chromium have been measured with both 412 keV and 60 keV gamma -radiation. When compared with the augmented plane-wave (APW) or linear combination of atomic orbitals band models, all three profiles show an expansion of the electron density distribution attributed to electron-electron correlation and most marked along the (111) nearest-neighbour direction. A new method of calculating anisotropic correlation effects in Compton profiles, which is based on the three-dimensional APW density of states, is reported and shown to reconcile experiment and theory.