| Автор | G M Meyer |
| Автор | R J Nelmes |
| Автор | C Vettier |
| Дата выпуска | 1980-07-30 |
| dc.description | The structure of the paraelectric (tetragonal) phase of KH<sub>2</sub>PO<sub>4</sub> has been investigated as a function of pressure using high-resolution (sin theta <sub>max</sub>/ lambda >1.0 Å<sup>-1</sup>) single-crystal neutron-diffraction techniques. The structure at approximately 14 kbar is compared with the structure at 1 bar (both determined at 295K). It has been assumed previously that the effect of pressure is to compress equally the O....O and H-H distances in the short, 'disordered' hydrogen bonds, with negligible change in the length (and orientation) of other interatomic distances. In contrast, the authors' findings are that the O....O distance is reduced by only 1/3 the amount predicted by this assumption; and the difference is accounted for by a significant rotation of the PO<sub>4</sub> groups around their 4 axes. There remains some uncertainty about the pressure dependence of H-H, the separation of the two half-occupancy sites generally used to model the H distribution. However, constrained refinements and significance testing, combined with other (empirical) evidence, show that the most probable change in H-H is a reduction that is (accidentally) close to that assumed in the earlier theoretical work. This conclusion is examined in the context of current theoretical models and the results of a parallel study of the temperature dependence of the KH<sub>2</sub>PO<sub>4</sub> structure. |
| Формат | application.pdf |
| Издатель | Institute of Physics Publishing |
| Название | A single-crystal neutron-diffraction study of the crystal structure of tetragonal KH<sub>2</sub>PO<sub>4</sub> at high pressure (approximately 14 kbar) |
| Тип | paper |
| DOI | 10.1088/0022-3719/13/21/009 |
| Print ISSN | 0022-3719 |
| Журнал | Journal of Physics C: Solid State Physics |
| Том | 13 |
| Первая страница | 4035 |
| Последняя страница | 4051 |
| Аффилиация | G M Meyer; Dept. of Phys., Univ. of Edinburgh, Edinburgh, UK |
| Аффилиация | R J Nelmes; Dept. of Phys., Univ. of Edinburgh, Edinburgh, UK |
| Аффилиация | C Vettier; Dept. of Phys., Univ. of Edinburgh, Edinburgh, UK |
| Выпуск | 21 |
