Rotational spectra

Thaddeus has reported six new carbon chains detected in the laboratory, all of astrophysical interest: CH, CH, CH, CH, HCN, and HCN. The microwave and millimeter wave frequencies of these molecules are now known to a fraction of 1 km s in radial velocity. HCN, which for 14 years has stood as the largest interstellar molecule, was unfortunately misidentified. The claimed lines in IRC+10216 and TMC-1 are some entirely different molecule -- the actual lines of HCN lie 0.13% lower in frequency, and are so far undetected. However, CH has been identified in IRC+10216 on the basis of the laboratory data, and it seems likely that some or all of the other chains on this list will be detected in the fairly near future. The CfA/Harvard group has also been involved in investigating other species, including NH, CH, CN, and HCS.

The submillimeter spectra of Orion/KL and other so-called ``hot core'' objects require detailed spectroscopy of complex organic molecules up to high frequencies. De Lucia, Herbst and co-workers have studied the submillimeter spectra of CHOD, CHCHCH, CHCN, trans- and gauche ethyl-alcohol, and DCOOCH. Spectra up to the terahertz region have been measured in the Cologne laboratory of SO, CN, and CHOH, and in Lille of NH. The microwave spectra of the simplest amino acid, glycine, have recently been measured by Lovas' for both conformers, enabling new astronomical searches.

The Lille group has also measured millimeter spectra of HCOCN, HSiO, SiH, CH, and NH.