SEARCH Articles Figures Tables 2R-CISD CASSCF-CISD CISD (Configuration Interaction with CISD (configuration interaction singles and CISD wave function CISDT, CISD GVB-CISD Hartree-Fock CISD correlation energy MR-CISD Open-shell CISD calculations Quadratic CISD Quadratic CISD method SR CISD Size-extensivity limited CISD methods