| DOI | Resolve DOI: https://doi.org/10.1103/PhysRevB.75.134108 |
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| Author | Search for: Tse, J.; Search for: Klug, Dennis1; Search for: Desgreniers, S.; Search for: Smith, J.; Search for: Flacau, Roxana1; Search for: Liu, Z.; Search for: Hu, J.; Search for: Chen, N.; Search for: Jiang, Di2 |
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| Affiliation | - National Research Council of Canada. NRC Steacie Institute for Molecular Sciences
- National Research Council of Canada. NRC Genomics and Health Initiative
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| Format | Text, Article |
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| Subject | ab initio calculations; calcium compounds; crystal structure; high-pressure solid-state phase transformations; hydrogen storage |
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| Abstract | The structural and vibrational properties of CaH2 have been examined up to 30 GPa at room temperature. Under ambient conditions, CaH2 has a Pnma (cotunnite-type) structure. A structural phase transformation was observed around 15 GPa and completed at 20 GPa. The high pressure structure is identified as hexagonal P63/mmc. First-principles calculations reproduced the first-order nature of the transition. Since P63/mmc is a supergroup of Pnma the structural change can be traced back to gradual displacements of the hydrogen atoms from the 4c positions in the cotunnite structure to the special 2a and 2d positions in the hexagonal structure. The observed phase transition pressure is much lower than that predicted for MgH2. |
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| Publication date | 2007-04-01 |
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| Publisher | American Physical Society |
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| In | |
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| Language | English |
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| Peer reviewed | Yes |
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| NPARC number | 12328372 |
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| Export citation | Export as RIS |
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| Report a correction | Report a correction (opens in a new tab) |
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| Record identifier | 301dbf7d-d26f-4ab6-ad31-c8b37ee7d372 |
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| Record created | 2009-09-10 |
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| Record modified | 2023-06-23 |
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