Lopes Joyce T, Romano Flavio, Grelet Eric, Franco Luís F M, Giacometti Achille
Universidade Estadual de Campinas, Faculdade de Engenharia Química, Departamento de Engenharia de Sistemas Químicos, Campinas, Brazil.
Dipartimento di Scienze Molecolari e Nanosistemi, Università Ca' Foscari Venezia Campus Scientifico, Edificio Alfa, via Torino 155, 30170 Venezia Mestre, Italy.
J Chem Phys. 2021 Mar 14;154(10):104902. doi: 10.1063/5.0040942.
Using isobaric Monte Carlo simulations, we map out the entire phase diagram of a system of hard cylindrical particles of length (L) and diameter (D) using an improved algorithm to identify the overlap condition between two cylinders. Both the prolate L/D > 1 and the oblate L/D < 1 phase diagrams are reported with no solution of continuity. In the prolate L/D > 1 case, we find intermediate nematic N and smectic SmA phases in addition to a low density isotropic I and a high density crystal X phase with I-N-SmA and I-SmA-X triple points. An apparent columnar phase C is shown to be metastable, as in the case of spherocylinders. In the oblate L/D < 1 case, we find stable intermediate cubatic (Cub), nematic (N), and columnar (C) phases with I-N-Cub, N-Cub-C, and I-Cub-C triple points. Comparison with previous numerical and analytical studies is discussed. The present study, accounting for the explicit cylindrical shape, paves the way to more sophisticated models with important biological applications, such as viruses and nucleosomes.
通过等压蒙特卡罗模拟，我们使用一种改进算法绘制了长度为（L）、直径为（D）的硬圆柱颗粒系统的完整相图，以识别两个圆柱之间的重叠条件。报道了长径比L/D > 1的长轴情况和L/D < 1的短轴情况的相图，不存在连续性解。在长径比L/D > 1的情况下，除了低密度各向同性I相和高密度晶体X相以及具有I-N-SmA和I-SmA-X三相点外，我们还发现了中间向列相N和近晶相SmA相。与球柱体情况一样，一个明显的柱状相C被证明是亚稳的。在短径比L/D < 1的情况下，我们发现了稳定的中间立方相（Cub）、向列相（N）和柱状相（C），具有I-N-Cub、N-Cub-C和I-Cub-C三相点。讨论了与先前数值和分析研究的比较。本研究考虑了明确的圆柱形状，为具有重要生物学应用（如病毒和核小体）的更复杂模型铺平了道路。
