TAIL BANDS OF THE DESLANDRES-D'AZAMBUJA SYSTEM OF THE C2 MOLECULE

Abstract

A number of new bands of the C2 molecule are analysed and found to represent tail bands of the Deslandres-d'Azambuja system. In consequence of the extension of this system thus obtained it was possible to improve considerably on the values of the rotational and vibrational constants of the upper and lower states 1IIg and 1IIu respectively. The vibrational quanta of the upper state are found to decrease rather rapidly, and a short extrapolation leads to a dissociation limit at 35,900 cm.−1 above the lower state 1IIu. From this and a recently suggested D0(C2) value, the energy difference between the 1IIu state and the 3IIu ground state is determined to be 13,700 cm.−1 = 1.7 e.v.