Analysis of a New Band System of theC2Molecule

Abstract

The 0-3, 0-4, 0-5 and 0-6 bands of a new band system of the ${\mathrm{C}}_2$ molecule are analyzed. The lower state, ${}_{}{}^3{}_{}{}^{}\Pi$, is the same as the lower state of the Swan bands (in all probability the ground state). The upper state is a new ${}_{}{}^3{}_{}{}^{}\Pi _g^{}{}_{}{}^{}$ state. The rotational and vibrational constants of the upper and lower state are given in Table VII. While the constants for the upper state are entirely new those for the lower state (ground state) are considerably improved over those at present in the literature. The triplet splitting and staggering in the new bands is much larger than in the Swan system. In the ${}_{}{}^3{}_{}{}^{}\Pi _0^{}{}_{}{}^{}-{}_{}{}^3{}_{}{}^{}\Pi _0^{}{}_{}{}^{}$ component a reversal of the staggering is observed. The electron configuration of the new state is briefly discussed. Finally a number of other bands, very probably due to ${\mathrm{C}}_2$, but not yet analyzed, are given.