New Observations on the Swan Bands of C2

The molecular spectra emitted by flash discharges of short duration through carbon dioxide gas are wholly those of C2, the Swan system predominating. Rotational structure extends to very high quantum numbers, and numerous small perturbations, some reported previously, are prominent. Eleven of these in the levels ν = 0–2 of the A3Πg state are discussed; eight are shown to arise through interactions with the recently described [Formula: see text] state.