title: A study of C3HD in cold interstellar clouds.
abstract: We have detected the 1(10)-1(01) transition of C3HD at 19.418 GHz at twelve positions in cold, dark clouds and resolved the D hyperfine components in two sources (L1498 and TMC-1C) well enough to derive values for the D quadrupole coupling constants.  Simultaneous observations of C3H2 in each source yield relative integrated line intensities in the range 0.10-0.18, from which we derive relative [C3HD]/[C3H2] abundances in the range 0.05-0.15.  These are among the highest deuteration ratios yet observed.  Within the limits of the observational and modeling uncertainties it is possible to explain the derived [C3HD]/[C3H2] ratios by ion-molecule chemistry if [e-] approximately 3 x 10(-7).
authors.affiliation: Herzberg Institute of Astrophysics, National Research Council of Canada.
authors.forename: M B
authors.initials: MB
authors.lastname: Bell
authors.forename: L W
authors.initials: LW
authors.lastname: Avery
authors.forename: H E
authors.initials: HE
authors.lastname: Matthews
authors.forename: P A
authors.initials: PA
authors.lastname: Feldman
authors.forename: J K
authors.initials: JK
authors.lastname: Watson
authors.forename: S C
authors.initials: SC
authors.lastname: Madden
authors.forename: W M
authors.initials: WM
authors.lastname: Irvine
mesh_terms: D055580:Astronomical Phenomena; D001256:Astronomy; D003903:Deuterium / Q000032:analysis* / Q000737:chemistry*; D005118:Extraterrestrial Environment; D006838:Hydrocarbons / Q000032:analysis*; D008962:Models, Theoretical; D013057:Spectrum Analysis
chemical_list: D006838:Hydrocarbons; D003903:Deuterium