Main Question or Discussion Point
So I'm trying to teach myself MO Theory and Spectroscopy. I was just wondering why symmetry was so important in understanding these and what characters are used to do. I know this is a broad question, but I've been reading a lot (Cotton, etc..) so I know they have to do with integrals and operators and stuff. But I'm having trouble explaining it when someone asks me -- I just want like a 30000 ft overview of why characters are useful in MO Theory and Spectroscopy. Can anyone help me out?