First Multireference Correlation Treatment of Bulk Metals
Voloshina, Elena and Paulus, Beate – 2014
Existence of the sp–d hybridization of the valence band states of the fcc Ca and Sr in the vicinity of the Fermi level indicates that their electronic wave function can have a multireference (MR) character. We performed a wave-function-based correlation treatment for these materials by means of the method of increments. As opposed to the single-reference correlation treatment (here, coupled cluster), which fails to describe cohesive properties in both cases, employing the MR averaged coupled pair functional, one can achieve almost 100% of the experimental correlation energy.