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Structure of high-density amorphous ice under pressure.
S Klotz1, G Hamel, J S Loveday
1Physique des Milieux Condensés, UMR 7602, Université P.M. Curie, B77, 4 Place Jussieu, 75252 Paris, France.
Physical Review Letters
|January 7, 2003
Summary
High-density amorphous ice (HDA) was studied under pressure using neutron diffraction. Compression significantly contracts the second coordination shell, leading to interpenetrating hydrogen bond networks.
Area of Science:
- Materials Science
- Condensed Matter Physics
- Chemistry
Background:
- Amorphous ices are structurally disordered forms of water ice.
- Understanding their behavior under pressure is crucial for planetary science and materials research.
- High-density amorphous ice (HDA) is a key phase relevant to these fields.
Purpose of the Study:
- To investigate the structural changes in high-density amorphous ice (HDA) under high pressure.
- To elucidate the role of coordination shells and hydrogen bonding in HDA compression.
- To provide insights into the molecular-level rearrangements within HDA.
Main Methods:
- In situ neutron diffraction experiments were conducted.
- High-density amorphous ice (HDA) samples were subjected to pressures up to 2.2 GPa.
- Neutron diffraction data were analyzed to determine structural parameters at 100 K.
Main Results:
- Compression of HDA primarily involves a significant contraction (approx. 20%) of the second neighbor coordination shell.
- The first coordination shell remains structurally intact during compression.
- Hydrogen bond orientations indicate no bonding between first and second shells, suggesting interpenetrating networks.
Conclusions:
- HDA compression is dominated by the collapse of the second coordination shell.
- The structure of HDA under pressure is characterized by increasingly interpenetrating hydrogen bond networks.
- These findings offer a detailed molecular-level understanding of amorphous ice behavior under extreme conditions.