抄録
The structures of rotational and vibrational energy levels and the term symbols to classify different electronic states are described for diatomic molecules. Different classes of parity, (+/−), (e/f) and (s/a), associated with each rovibronic level are discussed. The transition probability, the Franck-Condon factors, the Hönl-London factors and the transition moments of electronic transitions and their selection rules are described.
