Infrared diode laser spectroscopy of the Δυ = 2 band of NaBr using spectrum processing by Fourier transformation

The IR diode laser spectrum of the Δυ = 2 band of NaBr monomer has been observed with a heat-pipe high-temperature cell of a White cell type. Fringes due to optical reflections inside the high-temperature White cell were inherent in highly-sensitive observation of the spectrum. However, they were eliminated, as were high-frequency noises, by Fourier manipulation of the observed diode laser spectrum. The υ = 2-0 up to 6–4 vibration—rotation bands of both Na⁷⁹Br and Na⁸¹Br, 199 lines in total, were assigned in the range between 550 and 600 cm⁻¹. These data, combined with 21 mm wave data from the literature, were analysed with a least squares fit to nine Dunham Y _ij coefficients. Y₁₀ and Y₂₀ for Na⁷⁹Br were determined to be 298.73648(66) and −1.21058(19) cm⁻¹, respectively.