Displacement and distortion of the ammonium ion in rotational transition states in ammonium fluoride and ammonium chloride
| Autor: | R. J. C. Brown, Ruth M. Lynden-Bell, Ali Alavi |
|---|---|
| Rok vydání: | 1999 |
| Předmět: |
Quantitative Biology::Biomolecules
Physics::Medical Physics Inorganic chemistry Ab initio Analytical chemistry General Physics and Astronomy Rotational transition Ammonium fluoride Rotation Ion chemistry.chemical_compound chemistry Ab initio quantum chemistry methods Ammonium Ammonium chloride Physical and Theoretical Chemistry Physics::Atmospheric and Oceanic Physics |
| Zdroj: | The Journal of Chemical Physics. 110:5861-5865 |
| ISSN: | 1089-7690 0021-9606 |
| DOI: | 10.1063/1.478485 |
| Popis: | Ab initio density functional calculations have been carried out on ammonium fluoride to determine the equilibrium structure and the transition state for rotation of the ammonium ion. The calculated equilibrium geometry agrees satisfactorily with crystallographic data. Optimization of the crystal geometry in the transition state for rotation results in significant distortion and displacement of the ammonium ion within the unit cell. Upon reexamination of the rotational transition states in ammonium chloride, similar distortion and displacement of the ammonium ion are found. The rotation process is similar to a carousel motion, in which the ion moves along the rotation axis and changes shape as it rotates. These results show that rigid ion models for ammonium ion rotational dynamics in crystals are, at best, incomplete. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
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