HIGH-RESOLUTION FOURIER-TRANSFORM SPECTROSCOPY OF THE MEINEL SYSTEM OF OH

The infrared spectrum of the hydroxyl radical OH, between 1850 and 900 0 cm-1, has been measured with a Fourier transform spectrometer. The s ource, a hydrogen-ozone diffusion flame, was designed to study the exc itation of rotation-vibration levels of the OH Meinel bands under cond itions similar to those in the upper atmosphere which produce the nigh ttime OH airglow emission. Twenty-three bands were observed: nine band s in the DELTAupsilon = 1 sequence, nine bands in the DELTAupsilon = 2 sequence, and five bands in the DELTAupsilon = 3 sequence. A global n onlinear least-squares fit of 1696 lines yielded molecular parameters with a standard deviation of 0.003 cm-1. Term values are computed, and transition frequencies in the DELTAupsilon = 3, 4, 5, 6 sequences in the near-infrared are predicted.