Better approximations:
(+/-) Term symbol: 2S+1L(g/u) In the absence of spin-orbit coupling, the projection L of electronic angular momentum L on molecular axis is conserved. L (+/-) Term symbol: 2S+1L(g/u) L
Limiting cases of united atoms and separated atoms
N2 Lowest-energy configuration First two excited configurations All shells fully occupied (N2): 1Sg+ (...) : Pg state (multiplicity, see later) (...) : is similar to hole states are like those for , i.e. (see table)