Numerical Hartree–Fock calculations for N2, FH, and CO: Comparison with optimized LCAO results

The restricted Hartree–Fock equations for the ground states of N2, FH, and CO were solved numerically in prolate spheroidal coordinates. The series expansions employed converge rapidly, the maxium error in our orbitals being about 10−5 or less. The errors in our energies are smaller than 5×10−4 hartree. Comparisons of the energies, dipole quadrupole moments, and cusp ratios of our wavefunctions with the best available matrix LCAO results are presented. Our solutions, in most cases, significantly improve the cusp ratios and for N2 and CO lower the total energies by more than 10−3 hartree. Orbital density difference plots indicate the existence of significant errors in the LCAO orbitals, which are most apparent in the internuclear region.