检测TMC-1中的氘代甲基氰基乙炔CH $_2$ DC $_3$ N
Detection of deuterated methylcyanoacetylene, CH$_2$DC$_3$N, in TMC-1
摘要：
我们报告了在太空中首次探测到甲基氰基乙炔的单氘同位素，CH $_2$ DC $_3$ N。使用Yebes 40米射电望远镜在TMC-1中在31.0-50.4 GHz范围内共识别出该物种的15个转动跃迁，$J$ = 8-12，$K_a$ = 0和1。观察到的频率被用来推导出第一次的光谱参数的氘同位素。我们推导出$(8.0\pm 0.4) \times 10^{10}$ cm $^{-2}$的柱密度。CH $_3$ C $_3$ N和CH $_2$ DC $_3$ N之间的丰度比为$\sim$ 22。我们还从理论上计算了CH $_3$ C $_3$ N和CH $_3$ C $_4$ H的$^{13}$ C同位素体的主要光谱常数，以及CH $_3$ C $_4$ H的氘代同位素体的主要光谱常数，我们可以预期它们具有类似程度的氘代增强。然而，我们既没有检测到CH $_2$ DC $_4$ H，也没有检测到CH $_3$ C $_4$ D，也没有检测到任何$^{13}$ C同位素体。TMC-1中观察到的不同氘比合理地占气相化学模型，其中低温条件有利于通过与H $_2$ D $^+$反应的氘转移。
英文摘要：
We report the first detection in space of the single deuterated isotopologue of methylcyanoacetylene, CH$_2$DC$_3$N. A total of fifteen rotational transitions, with $J$ = 8-12 and $K_a$ = 0 and 1, were identified for this species in TMC-1 in the 31.0-50.4 GHz range using the Yebes 40m radio telescope. The observed frequencies were used to derive for the first time the spectroscopic parameters of this deuterated isotopologue. We derive a column density of $(8.0\pm 0.4) \times 10^{10}$ cm$^{-2}$. The abundance ratio between CH$_3$C$_3$N and CH$_2$DC$_3$N is $\sim$22. We also theoretically computed the principal spectroscopic constants of $^{13}$C isotopologues of CH$_3$C$_3$N and CH$_3$C$_4$H and those of the deuterated isotopologues of CH$_3$C$_4$H for which we could expect a similar degree of deuteration enhancement. However, we have not detected either CH$_2$DC$_4$H nor CH$_3$C$_4$D nor any $^{13}$C isotopologue. The different observed deuterium ratios in TMC-1 are reasonably accounted for by a gas phase chemical model where the low temperature conditions favor deuteron transfer through reactions with H$_2$D$^+$.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
