title: Observations of OCS and a search for OC3S in the interstellar medium.
abstract: Observations of OCS and a search for OC3S are reported, with particular reference to cold dust clouds.  OCS has been detected for the first time in dark clouds with a mean fractional abundance relative to hydrogen of approximately 3 x 10(-9); this is approximately 4 times greater than that observed for giant molecular clouds.  This results is discussed in the context of molecule formation mechanisms.  Observations  of the J = 1 --> 0 transition of OCS indicate that this transition is amplifying the background continuum radiation in the direction of Sgr B2.
authors.affiliation: Herzberg Institute of Astrophysics, National Research Council, Ottawa.
authors.forename: H E
authors.initials: HE
authors.lastname: Matthews
authors.forename: J M
authors.initials: JM
authors.lastname: MacLeod
authors.forename: N W
authors.initials: NW
authors.lastname: Broten
authors.forename: S C
authors.initials: SC
authors.lastname: Madden
authors.forename: P
authors.initials: P
authors.lastname: Friberg
mesh_terms: D055580:Astronomical Phenomena; D001256:Astronomy; D002244:Carbon / Q000737:chemistry; D019443:Cosmic Dust / Q000032:analysis*; D005118:Extraterrestrial Environment; D005740:Gases / Q000032:analysis; D006838:Hydrocarbons / Q000737:chemistry; D010100:Oxygen / Q000737:chemistry; D013057:Spectrum Analysis; D013440:Sulfides / Q000737:chemistry; D013455:Sulfur / Q000737:chemistry*; D013461:Sulfur Oxides / Q000737:chemistry*
chemical_list: D019443:Cosmic Dust; D005740:Gases; D006838:Hydrocarbons; D013440:Sulfides; D013461:Sulfur Oxides; D013455:Sulfur; D002244:Carbon; C010063:carbonyl sulfide; D010100:Oxygen