π* ↑  ↑  π*	π* ↑↓   π*	π* ↑  ↓  π*
Ground state	First excited state	Second excited state
2S + 1 = 3	2S + 1 = 1	2S + 1 = 1
3Σg−	1Δg, 92 kJmol−1 above ground state	1Σg+, 155 kJmol−1 above ground state