The Cologne Database for Molecular Spectroscopy (CDMS) contains a catalog of radio frequency and microwave to far-infrared spectral lines of atomic and molecular species that (may) occur in the interstellar or circumstellar medium or in planetary atmospheres. The catalog is continuously updated.
The General part provides information on the content and the format of the catalog, remarks on the partition function, and some equations useful for conversions.
The catalog section contains mostly rotational transition frequencies, uncertainties, intensities, and a wealth of other information of atomic and molecular species that may occur in the ISM or CSM or in planetary atmospheres
The documentation of molecular and atomic species can be found section SPECIES. Query the content of the catalog in section QUERY.