Deriving the Spectrum, Ch Diatomic rotation-vibration spectra and nuclear spin statistics
Problem
6Li2 has nuclear spin I=1 (a boson) and 15N2 has nuclear spin I=21 (a fermion); both are in a 1Σg+ ground electronic state.
((a)) Predict the ratio of the statistical weights of even- to odd-J rotational levels for each molecule, and state whether any levels are missing entirely.
((b)) State whether either molecule shows a pure rotational absorption spectrum or an infrared vibrational fundamental, and why.