Prebiotic Chemistry within a Simple Impacting Icy Mixture
Prebiotic Chemistry within a Simple Impacting Icy Mixture
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DOI：
10.1021/jp402976n
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发表时间：
2013-06-20
影响因子：
2.9
通讯作者：
Tamblyn, Isaac
中科院分区：
文献类型：
--
作者：
Goldman, Nir;Tamblyn, Isaac
我们目前的结果，前生物有机合成的冲击压缩混合物的简单冰从量子分子动力学（MD）模拟扩展到接近平衡的时间尺度。考虑到早期地球上可能存在不适宜居住的前生物大气层，彗星或其他冰冷天体的撞击过程可能是原始行星上前生物化学化合物的来源。我们观察到，适度的冲击压力和温度内的富含CO2的冰冷的混合物（36 GPa和2800 K）产生了一些含氮的杂环，其解离形成官能化的芳烃膨胀和冷却到环境条件下。相比之下，更高的冲击条件（48 - 60 GPa，3700 - 4800 K）导致长碳链分子，CH 4和甲醛的合成。在这些条件下的所有冲击压缩模拟都产生了大量的简单C-N键合化合物，如HCN，HNC和HNCO膨胀和冷却到环境条件。我们的研究结果阐明了一种机制，影响合成的益生元分子在现实的影响条件下，是独立的外部约束，如催化剂的存在下，照射紫外线辐射，或预先存在的条件在一个星球上。
We present results of prebiotic organic synthesis in shock compressed mixtures of simple ices from quantum molecular dynamics (MD) simulations extended to close to equilibrium time scales. Given the likelihood of an inhospitable prebiotic atmosphere on early Earth, it is possible that impact processes of comets or other icy bodies were a source of prebiotic chemical compounds on the primitive planet. We observe that moderate shock pressures and temperatures within a CO2-rich icy mixture (36 GPa and 2800 K) produce a number of nitrogen containing heterocycles, which dissociate to form functionalized aromatic hydrocarbons upon expansion and cooling to ambient conditions. In contrast, higher shock conditions (48-60 GPa, 3700-4800 K) resulted in the synthesis of long carbon-chain molecules, CH4, and formaldehyde. All shock compression simulations at these conditions have produced significant quantities of simple C-N bonded compounds such as HCN, HNC, and HNCO upon expansion and cooling to ambient conditions. Our results elucidate a mechanism for impact synthesis of prebiotic molecules at realistic impact conditions that is independent of external constraints such as the presence of a catalyst, illuminating UV radiation, or pre-existing conditions on a planet.