Herbst E, Adams N G, Smith D, DeFrees D J
Department of Physics, Duke University, USA.
Astrophys J. 1987 Jan 1;312(1):351-7. doi: 10.1086/164880.
Laboratory measurements and calculations have been performed to determine the abundance ratio of the deuterated ethynyl radical (CCD) to the normal radical (CCH) which can be achieved in dense interstellar clouds via isotopic fractionation in the C2H2+ (HD) = C2HD+ (H2) system of reactions. According to this limited treatment, the CCD/CCH abundance ratio which can be attained is in the range 0.02-0.03 for the Orion molecular cloud and 0.01-0.02 for TMC-1. These ranges of numbers are in reasonable agreement with the observed values in Orion and TMC-1. However, the analysis of the CCD/CCH abundance ratio is complicated via the presence of competing fractionation mechanisms, especially in the low-temperature source TMC-1.
已进行实验室测量和计算，以确定氘代乙炔基自由基（CCD）与正常自由基（CCH）的丰度比，该比值可通过C2H2+（HD） = C2HD+（H2）反应体系中的同位素分馏，在致密星际云中实现。根据这种有限的处理方法，对于猎户座分子云，可达到的CCD/CCH丰度比在0.02 - 0.03范围内，对于TMC - 1则在0.01 - 0.02范围内。这些数值范围与在猎户座和TMC - 1中观测到的值合理吻合。然而，由于存在竞争性分馏机制，特别是在低温源TMC - 1中，CCD/CCH丰度比的分析变得复杂。
