The Be[110] Compton profile was measured with high resolution utilizing x rays with energy of $16–18\mathrm{keV}$. The momentum resolution due to the experimental factors was set to 0.018 atomic units of momentum (a.u.). Electron final-state effects were estimated to have an approximate broadening effect of the spectral features equivalent to $0.028\mathrm{a.u.}$, resulting in a total momentum resolution of $0.033\mathrm{a.u.}$, i.e., more than a factor of 2 better than in previous Compton scattering studies. In this way, it was possible to study the ground-state momentum density of the electrons in metallic beryllium with a very high accuracy. As a result, the Fermi-surface-related fine structure is well observed in the experimental Compton profile and its derivative. However, the observed features are broader and less pronounced than anticipated by theoretical estimates. The remaining difference may be due to a non-negligible ground-state correlation and its effects on the momentum density and the Fermi surface of beryllium metal.

• Received 28 August 2007
• Corrected 12 December 2007

DOI:https://doi.org/10.1103/PhysRevB.76.235106