Idioma:

Translation-rotation coupling, phase transitions, and elastic phenomena in orientationally disordered crystals

Lynden-Bell, R. M. ; Michel, K. H.

Reviews of modern physics, 1994-07, Vol.66 (3), p.721-762 [Periódico revisado por pares]

United States

Texto completo disponível

Citações Citado por

Enviar para

Título:
Translation-rotation coupling, phase transitions, and elastic phenomena in orientationally disordered crystals
Autor: Lynden-Bell, R. M. ; Michel, K. H.
Assuntos: ALKALI METAL COMPOUNDS ; AMMONIUM COMPOUNDS ; AMMONIUM HALIDES ; CHARGED PARTICLES ; CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY ; CRYSTAL-PHASE TRANSFORMATIONS ; CRYSTALS ; CYANIDES ; DIELECTRIC PROPERTIES ; ELASTICITY ; ELECTRICAL PROPERTIES ; ENERGY ; ENERGY LEVELS ; EXCITED STATES ; FREE ENERGY ; HALIDES ; HALOGEN COMPOUNDS ; INTERMOLECULAR FORCES ; IONS ; MECHANICAL PROPERTIES ; MOLECULAR IONS ; NITRATES ; NITROGEN COMPOUNDS ; ORDER-DISORDER TRANSFORMATIONS ; OXYGEN COMPOUNDS ; PHASE TRANSFORMATIONS ; PHYSICAL PROPERTIES ; ROTATIONAL STATES ; SODIUM COMPOUNDS ; SODIUM NITRATES ; TENSILE PROPERTIES ; THERMODYNAMIC PROPERTIES 665000 -- Physics of Condensed Matter-- (1992-)
É parte de: Reviews of modern physics, 1994-07, Vol.66 (3), p.721-762
Notas: None
Descrição: Many of the properties of orientationally disordered crystals are profoundly affected by the coupling (known as translation-rotation coupling) between translation displacements and molecular orientation. The consequences of translation-rotation coupling depend on molecular and crystal symmetry, and vary throughout the Brillouin zone. One result is an indirect coupling between the orientations of different molecules, which plays an important role in the order/disorder phase transition, especially in ionic orientationally disordered crystals. Translation-rotation coupling also leads to softening of elastic constants and affects phonon spectra. This article describes the theory of the coupling from the point of view of the microscopic Hamiltonian and the resulting Landau free energy. Considerable emphasis is placed on the restrictions due to symmetry as these are universal and can be used to help one's qualitative understanding of experimental observations. The application of the theory to phase transitions is described. The softening of elastic constants is discussed and shown to be universal. However, anomalies associated with the order/disorder phase transition are shown to be restricted to cases in which the symmetry of the order parameter satisfies certain conditions. Dynamic effects on phonon spectra are described and finally the recently observed dielectric behavior of ammonium compounds is discussed. Throughout the article examples from published experiments are used to illustrate the application of the theory including well known examples such as the alkali metal cyanides and more recently discovered orientationally disordered crystals such as the fullerite, C[sub 60].
Editor: United States
Idioma: Inglês

Links

View this record in Osti.gov

Voltar para lista de resultados

Realização: Logos de Redes Sociais:

Translation-rotation coupling, phase transitions, and elastic phenomena in orientationally disordered crystals

Lynden-Bell, R. M. ; Michel, K. H.

United States

Buscando em bases de dados remotas. Favor aguardar.