Bell M B, Watson J K, Feldman P A, Matthews H E, Madden S C, Irvine W M
Herzberg Institute of Astrophysics, National Research Council of Canada, Ottawa, Ontario.
Chem Phys Lett. 1987 May 22;136(6):588-92. doi: 10.1016/0009-2614(87)80523-7.
The deuterium nuclear quadrupole hyperfine structure of the transition 1(10)-1(01) of the ring molecule cyclopropenylidene-d1 (C3HD) has been observed in emission from interstellar molecular clouds. The narrowest linewidths (approximately 7 kHz) so far observed are in the cloud L1498. The derived D coupling constants Xzz = 186.9(1.4) kHz, eta=0.063(18) agree well with correlations based on other molecules.