SCF-LCAO-MO wave functions for the bifluoride ion

Several SCF-LCAO-MO wave functions for the ground state of HF 2- are reported. The best one has a total energy∼4 ev higher than the estimated Hartree-Fock energy for HF2-, and it is about 30 ev lower than the energy corresponding to an SCF-LCAO-MO wave function with minimal basis set. These wave functions give indications as to what, in the SCF-LCAO-MO framework, is the smallest basis set which would give a wave function with total energy very near the Hartree-Fock energy. The importance of inclusion of a 2pπ STO on the hydrogen atom is discussed.