Rotational structure of CN emission from active nitrogen flames

The CN violet bands from active nitrogen flames have been studied. Rotational line intensities and rotational temperatures have been measured for a number of bands (0–1, 4–6, 5–7, 11-11, 12-12, and 13-13) at pressures ranging from 3 to 30 torr. The bands with ν′ >10show an anomalous rotational intensity distribution, which fits a mixture of two temperatures (one around 1200–3000 K and another near room temperature); bands with ν′<7 show a single temperature of 300–400 K. The relaxation of the high temperature group with pressure yields a relaxation time of the order of 10^?7s for CN molecules in the B-state. Excitation mechanisms for CN(B²σ⁺) are discussed.