title: Observations of some oxygen-containing and sulfur-containing organic molecules in cold dark clouds.
abstract: Observations of nine oxygen- and sulfur-containing organic molecules have been made toward the cold dark clouds TMC-1 and L134N.  We have confirmed the presence of para-ketene (H2C2O) in TMC-1, have for the first time observed ortho-ketene, and find a total ketene column density approximately 1 x 10(13) cm-2.  Thioformaldehyde (H2CS) is easily detectable in both TMC-1 and L134N, with a column density about 5 times larger in the former source (approximately 3 x 10(13) cm-2).  The fractional abundance of ketene is comparable to the predictions of ion-molecule chemistry, while that of thioformaldehyde in TMC-1 is one to two orders of magnitude greater than that expected from such models at steady state.  Interstellar sulfur chemistry thus continues to be poorly understood.  We set upper limits for the column densities of formic acid (HCOOH), vinyl alcohol (CH2CHOH), methyl formate (HCO2CH3), formamide (NH2CHO), methyl mercaptan (CH3SH), isothiocyanic acid (HNCS), and thioketene (H2C2S) in both sources.
authors.affiliation: Five College Radio Astronomy Observatory, University of Massachusetts, USA.
authors.forename: W M
authors.initials: WM
authors.lastname: Irvine
authors.forename: P
authors.initials: P
authors.lastname: Friberg
authors.forename: N
authors.initials: N
authors.lastname: Kaifu
authors.forename: K
authors.initials: K
authors.lastname: Kawaguchi
authors.forename: Y
authors.initials: Y
authors.lastname: Kitamura
authors.forename: H E
authors.initials: HE
authors.lastname: Matthews
authors.forename: Y
authors.initials: Y
authors.lastname: Minh
authors.forename: S
authors.initials: S
authors.lastname: Saito
authors.forename: N
authors.initials: N
authors.lastname: Ukita
authors.forename: S
authors.initials: S
authors.lastname: Yamamoto
mesh_terms: D055580:Astronomical Phenomena; D001256:Astronomy; D055598:Chemical Phenomena; D002621:Chemistry; D005030:Ethylenes; D005118:Extraterrestrial Environment; D005557:Formaldehyde / Q000031:analogs & derivatives*; D005559:Formamides; D005561:Formates; D005563:Formic Acid Esters; D017879:Isothiocyanates; D007659:Ketones; D010100:Oxygen; D013057:Spectrum Analysis; D013438:Sulfhydryl Compounds; D013455:Sulfur
chemical_list: D005030:Ethylenes; D005559:Formamides; D005561:Formates; D005563:Formic Acid Esters; D017879:Isothiocyanates; D007659:Ketones; D013438:Sulfhydryl Compounds; C030544:formic acid; D005557:Formaldehyde; C025468:methyl formate; C005231:methylmercaptan; C037152:isothiocyanic acid; C031066:formamide; D013455:Sulfur; C008223:ketene; D010100:Oxygen