Construction of self-interaction-corrected exchange-correlation functionals within the correlation factor approach

To model the exchange-correlation hole ρ_XC(r, u) of Kohn-Sham theory, we employ the correlation factor ansatz, which has recently been developed in our group. In this ansatz, ρ_XC(r, u) is written as a product of the correlation factor f_C(r, u) and an exchange-hole model ρ_X(r, u), i.e., ρ_XC(r, u) = f_C(r, u)ρ_X(r, u). In particular, we address the one-electron, self-interaction error and introduce a modified correlation factor model where f_C(r, u) is constructed such that it reduces identically to one in localized one-electron regions of a many-electron system. This self-interaction corrected exchange-correlation hole is then used to generate the corresponding exchange-correlation energy functional. The new functional is implemented into a Kohn-Sham program and assessed by calculating various molecular properties. We find that, overall, a significant improvement is obtained compared to previous versions of the correlation factor model.