Orbital polarization in narrow band systems: Application to the volume collapse in Ce

TLDR: In this article, the effect of Hund's second rule is included not only in the total energy, but also in the eigenvalue splittings which are required in the energy band calculation for the solid.

Abstract: A novel technique for treating orbital polarization is presented. The single electron eigenvalue shifts that emanated from the orbital polarization are of the form − E 3 Lm l , where E 3 is the Racah parameter, L is the orbital moment and m l the azimuthal quantum number. Thereby the effect of Hund's second rule is included not only in the total energy, but also in the eigenvalue splittings which are required in the energy band calculation for the solid. The calculations also incorporate the exchange and correlation potential in the local spin density approximation as well as the spin-orbit coupling. The self-consistently calculated equation-of-state for the light lanthanide Ce is presented. The observed volume collapse is well described by the parameter free calculations and accordingly the volume collapse in Ce is described as a Mott transition of the 4f electron.