= Solution
An example is the doubly occupied antibonding configuration $(\sigma_u)^2$, rather than the bonding $(\sigma_g)^2$ configuration dominant near equilibrium. It can be a self-consistent stationary determinant because symmetry makes the corresponding occupied-virtual Fock mixing vanish, while its bonding energy and nodal structure are inappropriate for the <ground state>. Solving the Hartree-Fock stationarity equations does not impose ground-state occupancy automatically.
Back to article page
