Fourier transform emission spectroscopy of the B2Σ+–X2Σ+ system of CN

Abstract The emission spectrum of the B 2 Σ + – X 2 Σ + system of CN has been observed at high-resolution using a Fourier transform spectrometer. The rotational structure of a large number of bands involving vibrational levels v  = 0–15 of both electronic states has been analyzed, and improved spectroscopic constants have been determined by combining the microwave and infrared measurements from previous studies. Improved spectroscopic constants for vibrational levels up to v ″ = 18 in the X 2 Σ + state and v ′ = 19 in the B 2 Σ + state have been determined by combining the measurements of the 16–13, 18–17, 18–18, 19–15, and 19–18 bands of Douglas and Routly [Astrophys. J. Suppl. 1 (1955) 295–318] and 17–14 and 17–16 bands of Ito et al. [J. Chem. Phys. 96 (1992) 4195] with our data. The band constants obtained have been used to estimate equilibrium ground state constants for CN.