Formation of Carbonic Acid (H_2CO_3) by Surface Reactions of Non-energetic OH Radicals with CO Molecules at Low Temperatures
Formation of Carbonic Acid (H_2CO_3) by Surface Reactions of Non-energetic OH Radicals with CO Molecules at Low Temperatures
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低温下非高能 OH 自由基与 CO 分子的表面反应形成碳酸 (H_2CO_3)
DOI：
10.1088/0004-637x/722/2/1598
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发表时间：
2010
期刊：
影响因子：
--
通讯作者：
V. Pirronello
中科院分区：
文献类型：
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作者：
Y. Oba;N. Watanabe;A. Kouchi;T. Hama;V. Pirronello
本文报道了10-40 K温度下CO分子与非能羟基自由基表面反应生成碳酸（H2 CO 3）的实验结果。在红外光谱和热程序脱附质谱中都清楚地确定了H2 CO 3的形成。H2 CO 3的产率相当高，约为CO与OH反应生成CO2的40%~ 70%。CO与OH反应生成的H2 CO 3的结构可能不同于H2O/CO2二元冰的高能过程如紫外线照射、离子照射和电子照射所形成的结构。本文设想了H2 CO 3在星际介质中的一些可能作用，如通过与碱性物质的酸碱反应使新分子的颗粒地幔富集，以及促成了6.8 μm处未识别谱带的形成;我们提出了尚未探测到H2 CO 3的可能原因，并讨论了碳酸分子在气相中的恢复。
We present the experimental results of carbonic acid (H 2 CO 3) formation through surface reactions of CO molecules with non-energetic hydroxyl (OH) radicals at 10–40 K. The formation of H 2 CO 3 was clearly identified both in the IR spectra and in the thermally programmed desorption mass spectra. The H 2 CO 3 yield was rather high, amounting to approximately 40%–70% relative to that of CO 2 formed by the reaction of CO with OH. The structure of H 2 CO 3 formed by reactions of CO with OH may differ from that formed by energetic processes such as UV irradiation, ion irradiation, and electron irradiation of H 2 O/CO 2 binary ices. In this paper, we envisage some of the possible roles H 2 CO 3 may have in the interstellar medium, such as enriching grain mantles of new molecules via acid–base reactions with basic species and contributing to the formation of the unidentified band at 6.8 μm; we suggest possible reasons for its non-detection yet and discuss the restoration of carbonic acid molecules in the gas phase.