11:46 AM
symmetry alone doesn't help you here
it can just help a bit, the higher the more it can
OK now as a matter of fact B1g is the ground state
and the NEXT excited state (as a matter of fact) is A1g
((BUT we will see that we could now just try any of the possible combinations ...))
((for ground and excited states, I mean))
That means that we seek q such that