Related Experiment Video
Updated: Feb 18, 2026
08:46
Methane Hydrate Crystallization on Sessile Water Droplets
Published on: May 26, 2021
2.9K
Revisiting the Phase Diagram of Methane
Mengnan Wang1,2, Miriam Peña-Alvarez1, Ross T Howie1,3
1University of Edinburgh, Centre for Science at Extreme Conditions and School of Physics and Astronomy, Edinburgh, United Kingdom.
Physical Review Letters
|February 16, 2026
Summary
This study investigated methane
Area of Science:
- Geophysics
- Materials Science
- Physical Chemistry
Background:
- Understanding methane's phase behavior under extreme conditions is crucial for planetary science and materials research.
- Previous studies on methane's melting curve and solid phases have yielded inconsistent results.
Purpose of the Study:
- To investigate the melting curve and solid phases of methane up to 45 GPa and 1100 K.
- To clarify the discrepancies in previous methane phase diagram data.
Main Methods:
- Combined in situ high-temperature, high-pressure optical spectroscopy (Raman) with visual observations.
- Experiments conducted up to 45 GPa and 1100 K to map phase transformations and equilibrium states.
Main Results:
- Methane's melting curve extends to significantly higher temperatures than previously reported.
- Phase transitions to higher pressure phases (VII, VIII, IX) are highly dependent on the pressure-temperature-time path.
- Photochemical dissociation and light-induced reactions may explain inconsistencies in prior data.
Conclusions:
- The study provides a more accurate phase diagram for methane under extreme conditions.
- Kinetic effects significantly influence methane's phase transformations.
- High-intensity light sources can affect experimental results, necessitating careful consideration.
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