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The advent of high-resolution spectrographs and detailed stellar atmosphere modelling has strengthened the need for accurate molecular data. Carbon-enhanced metal-poor (CEMP) stars spectra are interesting objects with which to study transitions from the CH molecule. We combine programs for spectral analysis of molecules and stellar-radiative transfer codes to build an extensive CH linelist, including predissociation broadening as well as newly identified levels. We show examples of strong predissociation CH lines in CEMP stars, and we stress the important role played by the CH features in the Bond-Neff feature depressing the spectra of barium stars by as much as 0.2 mag in the λ = 3000−5500 Å range. Because of the extreme thermodynamic conditions prevailing in stellar atmospheres (compared to the laboratory), molecular transitions with high energy levels can be observed. Stellar spectra can thus be used to constrain and improve molecular data.

Absorption cross sections of SO2 have been recorded at 295 K at the resolutions of 2 and 16 cm−1. The 27000‐ to 40000‐cm−1 spectral region has been investigated. The comparison with data available from the literature shows a good agreement between the different data sets (less than 5%). However, local discrepancies, for example at the peaks of absorption, can reach 20%.

New long path length, high resolution, Fourier transform spectrometer measurements for water are presented. These spectra cover the near infrared, visible, and near ultraviolet regions and contain water transitions belonging to all polyads from 3 to 8. Transitions in the range 13 100-21 400 cm Ϫ1 are analyzed using line lists computed using variational first-principles calculations. 2286 new transitions are assigned to H 2 16 O. These result in the observation of transitions in 15 new overtone and combination bands of water. Energy levels for these and other newly observed levels are presented. It is suggested that local mode rather than normal mode vibrational assignments are more appropriate for the vibrational states of water in polyads 4 and above.

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