Vishwakarma Gaurav, Malla Bijesh K, Reddy K S S V Prasad, Ghosh Jyotirmoy, Chowdhury Soham, Yamijala Sharma S R K C, Reddy Sandeep K, Kumar Rajnish, Pradeep Thalappil
DST Unit of Nanoscience (DST UNS) and Thematic Unit of Excellence (TUE), Department of Chemistry, Indian Institute of Technology Madras, Chennai 600036, India.
Department of Chemistry, Indian Institute of Technology Madras, Chennai 600036, India.
J Phys Chem Lett. 2023 Mar 23;14(11):2823-2829. doi: 10.1021/acs.jpclett.3c00373. Epub 2023 Mar 13.
Restricted migration of reactive species limits chemical transformations within interstellar and cometary ices. We report the migration of CO from clathrate hydrate (CH) cages to amorphous solid water (ASW) in the presence of tetrahydrofuran (THF) under ultrahigh vacuum (UHV) and cryogenic conditions. Thermal annealing of sequentially deposited CO and HO ice, CO@HO, to 90 K resulted in the partitioning of CO in 5 and 56 CH cages (CO@5, CO@56). However, upon preparing a composite ice film composed of CO@5, CO@56 and THF distributed in the water matrix at 90 K, and annealing the mixture for 6 h at 130 K produced mixed CO-THF CH, where THF occupied the 56 cages (THF@56) exclusively while CO in 56 cages (CO@56) got transferred to the ASW matrix and CO in the 5 cages (CO@5) remained as is. This cage-matrix exchange may create a more conducive environment for chemical transformations in interstellar environments.
活性物种的受限迁移限制了星际和彗星冰中的化学转化。我们报告了在超高真空（UHV）和低温条件下，在四氢呋喃（THF）存在的情况下，一氧化碳（CO）从笼形水合物（CH）笼迁移到无定形固态水（ASW）中的情况。将依次沉积的CO和HO冰（CO@HO）热退火至90 K，导致CO在5个和56个CH笼中分配（CO@5，CO@56）。然而，在90 K下制备由分布在水基质中的CO@5、CO@56和THF组成的复合冰膜，并在130 K下将混合物退火6小时后，产生了混合的CO-THF CH，其中THF仅占据56个笼（THF@56），而56个笼中的CO（CO@56）转移到ASW基质中，5个笼中的CO（CO@5）保持不变。这种笼-基质交换可能会在星际环境中为化学转化创造更有利的环境。
