CRITICAL-BEHAVIOR OF A SYSTEM WITH ORIENTATIONAL AND POSITIONAL DEGREES OF FREEDOM - A MONTE-CARLO SIMULATION STUDY

Article

关键词: DISCRETE-LATTICE MODEL;    SMECTIC-A TRANSITION;    PHASE-TRANSITIONS;    PLASTIC CRYSTALS;    GAS MODEL;    CROSSOVER;    EXPONENTS;    ORDER;   

DOI  :  10.1103/PhysRevB.43.13335

来源: SCIE

【 摘 要 】

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.

【 授权许可】

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