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Updated: Jun 25, 2025
08:46
Methane Hydrate Crystallization on Sessile Water Droplets
Published on: May 26, 2021
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Partitioning photochemically formed CO2 into clathrate hydrate under interstellar conditions
Gaurav Vishwakarma1, Bijesh K Malla1, Rajnish Kumar2,3
1DST Unit of Nanoscience (DST UNS) and Thematic Unit of Excellence (TUE), Department of Chemistry, Indian Institute of Technology Madras, Chennai 600036, India. pradeep@iitm.ac.in.
Physical Chemistry Chemical Physics : PCCP
|May 22, 2024
Summary
Clathrate hydrates (CHs) form from CO2 produced by UV irradiation of ice. This process, occurring under simulated interstellar conditions, suggests CHs may alter astrophysical environments.
Area of Science:
- Astrochemistry
- Materials Science
Background:
- Clathrate hydrates (CHs) are host-guest compounds of water forming cages around guest molecules.
- CHs are known to exist under interstellar conditions, with previous studies showing their formation via thermal treatment.
- However, the photochemical formation pathways of CHs in astrophysical environments remain less understood.
Purpose of the Study:
- To investigate the photochemical formation of CO2 clathrate hydrates (CHs) under simulated interstellar conditions.
- To explore the role of UV irradiation and ice composition on CH formation.
- To understand how photoproducts influence CH stability and astrophysical environments.
Main Methods:
- Simulated interstellar conditions using vacuum ultraviolet irradiation of H2O-CO mixtures at 10 K and ~10^-10 mbar.
- Studied the process at varying temperatures and H2O-CO compositions.
- Confirmed CO2 CH formation and identified photoproducts using reflection absorption infrared spectroscopy.
Main Results:
- CO2 produced photochemically partitioned into CH and amorphous ice matrix phases.
- UV-induced photodesorption of CO2 provided mobility for CH formation.
- Photoproducts, such as methanol, were observed to stabilize the CH structures.
Conclusions:
- Photochemical processing of H2O-CO ice mixtures can lead to the formation of CO2 clathrate hydrates.
- This pathway is significant for understanding the chemical evolution of icy bodies in astrophysical environments.
- The formation of CHs and other photoproducts can alter the chemical composition of interstellar ices.
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