Next: Totally symmetric singlets for
Valence states are defined as the weighted average of all
CSFs arising from an electronic configuration (occupation): (MO)n.
This is identical to the average energy of all Slater determinants.
|a = b =
This covers, e.g. the cases n = 1 and
n = 2nir - 1: p1, p5,
d1, d9, etc, since there is only a single CSF which is identical
to the average of configurations.