Electron momentum density and Compton profile by a semi-empirical approach

• Electron momentum densities of pure metals are described by a semi-empirical approach.
• This approach is similar to a Fermi–Dirac distribution with two parameters modified.
• We tested the approach for all metals with Z=3–50 and find good agreement in all cases.
• The present semi-empirical method captures pairing correlation effects.

Here we propose a semi-empirical approach to describe with good accuracy the electron momentum densities and Compton profiles for a wide range of pure crystalline metals. In the present approach, we use an experimental Compton profile to fit an analytical expression for the momentum densities of the valence electrons. This expression is similar to a Fermi–Dirac distribution function with two parameters, one of which coincides with the ground state kinetic energy of the free-electron gas and the other resembles the electron–electron interaction energy. In the proposed scheme conduction electrons are neither completely free nor completely bound to the atomic nucleus. This procedure allows us to include correlation effects.We tested the approach for all metals with Z=3–50 and showed the results for three representative elements: Li, Be and Al from high-resolution experiments.