Cecchi-Pestellini, CesareDalgarno, Alexander2017-02-212002Cecchi-Pestellini, Cesare, and Alexander Dalgarno. 2002. “C2absorption-Line Diagnostics of Diffuse Interstellar Clouds.” Monthly Notices of the Royal Astronomical Society 331 (3) (April): L31–L34. doi:10.1046/j.1365-8711.2002.05418.x.0035-8711http://nrs.harvard.edu/urn-3:HUL.InstRepos:30403734The excitation of the diatomic carbon molecule in diffuse interstellar clouds is discussed for a cloud with large density fluctuations of small linear filling factor along the line of sight. Possible implications for the chemistry of the diffuse cloud in front of Cygnus OB2 No. 12 are discussed.en-USmolecular processesISM: cloudsISM: individual: Cygnus OB2 No. 12ISM: moleculesJournal Article2017-02-2110.1046/j.1365-8711.2002.05418.x