Observations of NH2D toward Dark Molecular Clouds

摘要: The 1-1 transition of NH2D at 110.1536 GHz was surveyed toward 16 cores high ammonia abundance in 14 cold dark clouds and detected eight cloud cores, L1448, B1, L1489N, L1551N, L1641N, L134N(S), ρ Oph E, L63, where L134N L63 are not associated with infrared sources. column densities were compared those the main species NH3, previously determined for corresponding sources, relative abundance, [NH2D]/[NH3], found to be large, 0.025-0.18, which is among highest deuterium fractionation so far observed. remarkably larger than a predicted value by latest gas-phase chemical model Howe & Millar. spectral line other cores. These results suggest that part NH3 could originate from dust related reactions energetic events.