Rotationally resolved A2?u <- X2?g electronic transition of NC6N+.

The rotationally resolved A 2 ∏ u X 2 ∏ g electronic origin band spectrum of dicyanodiacetylene cation, NC 6 N + , has been recorded in the gas phase using frequency-production double modulation spectroscopy in a liquid nitrogen cooled hollow cathode discharge and cavity ring down spectroscopy in a supersonic plasma. The analysis of the complementary results provides accurate molecular parameters for the two spin-orbit components in both electronic states.