Molecular Rydberg states energy values

The energy of the electronic transition itself corresponds, as with atomic spectra, to the difference of two terms characteristic respectively of an upper and a lower state. The molecular states present close analogies with the 8, P, D,... states of atoms, and the values of A g are generally of the same order of magnitude as those which determine atomic spectra. Higher terms sometimes fall into sequences of the Rydberg type, so that they evidently do not differ fundamentally from atomic terms. 

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