A study of C3HD in cold interstellar clouds.
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).
Bell
M B
MB
Herzberg Institute of Astrophysics, National Research Council of Canada.
Avery
L W
LW
Matthews
H E
HE
Feldman
P A
PA
Watson
J K
JK
Madden
S C
SC
Irvine
W M
WM
D055580:Astronomical Phenomena; D001256:Astronomy; D003903:Deuterium / Q000032:analysis* / Q000737:chemistry*; D005118:Extraterrestrial Environment; D006838:Hydrocarbons / Q000032:analysis*; D008962:Models, Theoretical; D013057:Spectrum Analysis
D006838:Hydrocarbons; D003903:Deuterium