To date more than 160 molecular species have been identified in interstellar, circumstellar, and cometary clouds by means of their ro-vibronic spectra. The majority of these, about 135 species have been detected by means of their rotational spectrum in the microwave region. These identifications rely heavily on laboratory studies and spectral predictions based on the laboratory data.
Current astronomical studies involve a deep survey toward Sagittarius B2(N), one of the richest molecular clouds known and often referred to as the "Large Molecule Heimat (Homeland)". In 2007 the Prebiotic Interstellar Molecule Survey (PRIMOS) was awarded 625 hours of time on the Green Bank Telescope (GBT) operated by the National Radio Astronomy Observatory (NRAO). This project is about 30% to 40% complete and has contributed to the detection of CNCHO (formyl cyanide) and a high energy conformer of methyl formate. Collaborators on this project are A. J. Remijan (NRAO), P. R. Jewell (NRAO), and J. M. Hollis (NASA Goddard). Data from this legacy survey is made available quarterly on the web site: The GBT PRIMOS Project.
Laboratory studies are carried out on the NIST pulsed-beam Fourier transform microwave (FTWM) spectrometers and the broadband chirped-pulse FTMW spectrometer at the University of Virginia under the Center for Chemistry of the Universe (CCU). Current experiments involve sugars (erythrose) and sugar alcohols (propanediols).
Efforts also continue in developing spectroscopic databases for aiding the identification of spectral features of known interstellar species as well as potential interstellar species. For more details, see Frequencies for observed interstellar molecular microwave transitions.