| Autor: |
Kamoun, M., Ghozlen, M. H. Ben, Daoud, A. |
| Zdroj: |
Phase Transitions: A Multinational Journal; January 1987, Vol. 9 Issue: 3 p247-252, 6p |
| Abstrakt: |
The second-order phase transition at 265 K in the triammonium hydrogen disulfate compound (NH4)3H(SO4)2 has been observed by X-ray diffractometry. The space group below 265 K is identified to be P2/b. The recorded X-ray diagrams show a doubling of the primitive unit cell. The observed symmetry change has been described by the Landau theory of continuous phase transitions. The implied high-symmetry point of the corresponding first Brillouin zone shows other possible space groups for the low-temperature structure which are in agreement with Landau and Lifshitz criteria.All the theoretical results are discussed and compared with the obtained space group. |
| Databáze: |
Supplemental Index |
| Externí odkaz: |
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