Department of Science and Technology (DST) Unit of Nanoscience and Thematic Unit of Excellence (TUE), Department of Chemistry, Indian Institute of Technology Madras, Chennai 600036, India.
Department of Chemical Engineering, Indian Institute of Technology Madras, Chennai 600036, India.
Proc Natl Acad Sci U S A. 2019 Jan 29;116(5):1526-1531. doi: 10.1073/pnas.1814293116. Epub 2019 Jan 10.
Clathrate hydrates (CHs) are ubiquitous in earth under high-pressure conditions, but their existence in the interstellar medium (ISM) remains unknown. Here, we report experimental observations of the formation of methane and carbon dioxide hydrates in an environment analogous to ISM. Thermal treatment of solid methane and carbon dioxide-water mixture in ultrahigh vacuum of the order of 10 mbar for extended periods led to the formation of CHs at 30 and 10 K, respectively. High molecular mobility and H bonding play important roles in the entrapment of gases in the in situ formed 5 CH cages. This finding implies that CHs can exist in extreme low-pressure environments present in the ISM. These hydrates in ISM, subjected to various chemical processes, may act as sources for relevant prebiotic molecules.
笼形水合物（CHs）在高压条件下普遍存在于地球中，但它们在星际介质（ISM）中的存在尚不清楚。在这里，我们报告了在类似于 ISM 的环境中甲烷和二氧化碳水合物形成的实验观察结果。在 10 mbar 左右的超高真空下对固体甲烷和二氧化碳-水混合物进行热处理，并延长处理时间，分别在 30 和 10 K 下形成了 CHs。高分子迁移率和氢键在气体捕获到原位形成的 5 CH 笼中发挥了重要作用。这一发现意味着 CHs 可以存在于 ISM 中存在的极端低压环境中。ISM 中的这些水合物可能会受到各种化学过程的影响，从而成为相关前生物分子的来源。
