Electrical response of molecular systems:: The power of self-interaction corrected kohn-sham theory

The accurate prediction of electronic response properties of extended molecular systems has been a challenge for conventional, explicit density functionals. We demonstrate that a self-interaction correction (SIC) implemented rigorously within Kohn-Sham theory via the optimized effective potential (OEP) yields polarizabilities close to the ones from highly accurate wave-function-based calculations and exceeding the quality of exact-change OEP. The orbital structure obtained with the OEP-SIC functional and approximations to it are discussed.