Ethane under pressure revisited using x-ray diffraction, Raman spectroscopy, infrared absorption, and ab initio
Loïc Toraille1,2, Gunnar Weck1,2, Grégory Geneste1,2
1CEA DAM, DIF, F-91297 Arpajon, France.
The Journal of Chemical Physics
|June 3, 2024
Summary
High-pressure ethane (C2H6) properties were studied up to 150 GPa. Researchers revealed the distortion mechanism between tetragonal and monoclinic phases and observed no further phase transitions.
Area of Science:
- Materials Science
- High-Pressure Physics
- Quantum Chemistry
Background:
- Ethane (C2H6) is predicted to be a stable carbon-hydrogen compound at high pressures.
- Experimental data on ethane's properties under extreme pressure remains limited.
Purpose of the Study:
- To comprehensively investigate the structural and vibrational characteristics of ethane at pressures up to 150 GPa.
- To elucidate the phase transition mechanisms and compression behavior of ethane under pressure.
Main Methods:
- Single-crystal X-ray diffraction was employed to analyze structural changes.
- Raman spectroscopy and infrared absorption were used to study vibrational modes.
- Ab initio calculations were performed for theoretical validation.
Main Results:
- The distortion mechanism between tetragonal and monoclinic phases (3.2–5.2 GPa) was identified.
- No additional phase transitions were observed up to 150 GPa.
- An unusual anticrossing phenomenon between vibrational modes near 40 GPa was detected.
Conclusions:
- Ethane exhibits a specific distortion mechanism at moderate pressures but remains stable up to 150 GPa.
- Intermolecular interactions, potentially via hydrogen bonding, influence vibrational mode behavior at high pressures.
- The study provides crucial experimental data for validating theoretical models of high-pressure carbon-hydrogen systems.
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