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Orientational Disorder and Structural Phase Transitions in Plastic Molecular Crystals

  • Mauro Ferrario
Chapter
Part of the NATO ASI Series book series (NSSE, volume 205)

Abstract

Order-Disorder phase transition in molecular systems, such as structural phase transformations in molecular solids or nematic-isotropic transitions in liquid crystal, can be studied in details by means of constant pressure-constant temperature molecular dynamics computer simulation. A number of microscopically defined order parameters can be computed in order to describe the transitions within the framework of Landau theory. Simulation allows to study in details the orientational motion and the diffuse scattering observed in neutron and X-ray scattering experiments in the high temperature orientationally disordered solid phases, and to quantify the role of the translation-rotation coupling in the ordering processes. Strong coupling , when present, may be held responsible for the appearance of metastable phases on cooling of the disordered system. In these cases it is possible to show that the mechanism of phase transition can be completely controlled by pre-ordering processes in the disordered phase

Keywords

Plastic Crystal Diffuse Scattering Structural Phase Transformation Orientational Distribution Orientational Order Parameter 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© Springer Science+Business Media Dordrecht 1991

Authors and Affiliations

  • Mauro Ferrario
    • 1
  1. 1.Istituto di Fisica TeoricaUniversità di MessinaS. Agata-MessinaItaly

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