The temperature dependence of the vibrational wavenumbers, of the anharmonic and/or order-disorder origin of the damping and of the Raman intensities are brieÑy presented. On that basis, it is then shown that one can obtain information such as the height of the potential barrier, the orientational c
Order and disorder in structural phase transitions
✍ Scribed by Y. Yacoby; B. Rechav; N. Sicron; E.A. Stern; J.J. Rehr; B. Ravel
- Publisher
- Elsevier Science
- Year
- 1995
- Tongue
- English
- Weight
- 278 KB
- Volume
- 208-209
- Category
- Article
- ISSN
- 0921-4526
No coin nor oath required. For personal study only.
✦ Synopsis
Fundamental aspects of structural phase transitions are discussed in view of XAFS measurements of the local structure below and above To. The experimental results show that the local structure and the order parameter have very different temperature dependencies. In particular, while the order parameter is zero above Tc the local structure remains distorted hundreds of degrees above the transition. This means that the local crystal distortions are disordered above Tc and partially disordered below it. This behavior has been observed in pure and mixed crystals and in ferroelectric as well as antiferrodistortive type crystals suggesting that it may be quite general.
📜 SIMILAR VOLUMES
## Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable v
Order+disorder structural phase transitions in alkali perchlorates MClO 4 (M ؍ Na, K, Rb, Cs) are investigated using molecular dynamics simulation. The potentials in the simulations are based on the Gordon+Kim modi5ed electron gas formalism extended to molecular ions. The simulations yield 5rst-or