title: The unidentified diffuse interstellar bands as evidence for large organic molecules in the interstellar medium.
abstract: Since 1921, astronomers have been aware of a set of spectral absorption features that are formed in interstellar space but are not identifiable with any known atomic or molecular species. Today some 200 of these so-called diffuse interstellar bands (DIBs) are known, yet none has yet been identified unambiguously with any specific carrier. Recent evidence from astronomical observations, laboratory spectroscopy, and chemical studies suggests that the responsible species are large carbon-bearing molecules. This paper provides a brief history of the DIB problem, a review of suggested carriers, and a description and discussion of new results from the telescope and from laboratory measurements of chemical reaction rates in candidate carriers.
authors.affiliation: Center for Astrophysics and Space Astronomy, University of Colorado, Boulder 80309, USA. tsnow@casa.colorado.edu
authors.forename: T P
authors.initials: TP
authors.lastname: Snow
mesh_terms: D000042:Absorption; D000838:Anions / Q000737:chemistry; D055580:Astronomical Phenomena; D001256:Astronomy; D019411:Clinical Laboratory Techniques; D019443:Cosmic Dust / Q000032:analysis*; D006838:Hydrocarbons / Q000737:chemistry*; D006859:Hydrogen / Q000737:chemistry; D011084:Polycyclic Aromatic Hydrocarbons / Q000737:chemistry*
chemical_list: D000838:Anions; D019443:Cosmic Dust; D006838:Hydrocarbons; D011084:Polycyclic Aromatic Hydrocarbons; D006859:Hydrogen