Hi @EigenState137. I would like to express my sincere thanks to you for all your help and discussions on this thread. Particularly, now I realize that you were 100% correct about almost every aspect. Recently I was reading a laser diagnostic book, and now my understanding is much deeper.
Also...
I found this kind of notation (P21, R21 and so on) in many papers, such as this one: https://www.sciencedirect.com/science/article/abs/pii/S000926149700239X
I agree with you, Twigg, that it might be a different convention rather than a hyper fine structure. As a paper I read mentioned that...
Thank you ES for your answer, but still not quite sure.
1. Does the hyperfine rovibronic spectrum necessarily mean 2-photon excitation? Can using a single photon excite a molecule and arrive the same results?
2. I was looking at LIF-base CH C-X (0,0) transitions, which shows all the 12...
I have a bit basic understanding of spectrum, but quite confused with LIF spectrum. It seems existing 12 main branches of Laser induced fluorescence, such P1, P2, Q1, Q2, P21, R21，and so on. I know there should be O P Q R S branches of the rotational transitions, but where these so many...