Critical behavior of a system with orientational and positional degrees of freedom: A Monte Carlo simulation study

The critical behavior of a system constituted by molecules with a preferred symmetry axis is studied by means of a Monte Carlo simulation of a simplified two-dimensional model. The system exhibits two phase transitions, associated with the vanishing of the positional order of the center of mass of t...

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Detalles Bibliográficos
Autores: Vives i Santa-Eulàlia, Eduard, Planes Vila, Antoni
Tipo de recurso: artículo
Estado:Versión publicada
Fecha de publicación:1991
País:España
Institución:Universidad de Barcelona
Repositorio:Dipòsit Digital de la UB
OAI Identifier:oai:diposit.ub.edu:2445/9831
Acceso en línea:https://hdl.handle.net/2445/9831
Access Level:acceso abierto
Palabra clave:Transformacions de fase (Física estadística)
Mètode de Montecarlo
Cristalls líquids
Phase transformations (Statistical physics)
Monte Carlo method
Liquid crystals
Descripción
Sumario:The critical behavior of a system constituted by molecules with a preferred symmetry axis is studied by means of a Monte Carlo simulation of a simplified two-dimensional model. The system exhibits two phase transitions, associated with the vanishing of the positional order of the center of mass of the molecules and with the orientational order of the symmetry axis. The evolution of the order parameters and the specific heat is also studied. The transition associated with the positional degrees of freedom is found to change from a second-order to a first-order behavior when the two phase transitions are close enough, due to the coupling with the orientational degrees of freedom. This fact is qualitatively compared with similar results found in pure liquid crystals and liquid-crystal mixtures.