GPU-Accelerated Molecular Dynamics Simulation to Study Liquid Crystal Phase Transition Using Coarse-Grained Gay-Berne Anisotropic Potential.
GPU-Accelerated Molecular Dynamics Simulation to Study Liquid Crystal Phase Transition Using Coarse-Grained Gay-Berne Anisotropic Potential.
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GPU 加速分子动力学模拟利用粗粒 Gay-Berne 各向异性势研究液晶相变
DOI：
10.1371/journal.pone.0151704
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发表时间：
2016
期刊：
影响因子：
3.7
通讯作者：
Li Y
中科院分区：
文献类型：
--
作者：
Chen W;Zhu Y;Cui F;Liu L;Sun Z;Chen J;Li Y
Gay-Berne (GB) 势被认为是各向异性粒子模拟中的精确模型，尤其是液晶 (LC) 介晶。然而，其计算复杂性导致大型系统的过程极其耗时。在这里，我们开发了一种 GPU 加速的分子动力学 (MD) 模拟，在 GALAMOST 包中实现了粗粒度 GB 势，以研究小分子、主链或侧链聚合物中介晶的液晶相变。对于三种不同分子中的相同介晶，在从完全各向同性熔体冷却时，小分子形成单域近晶-B相，而主链液晶聚合物由于相邻介晶中的连接约束而更喜欢单域向列相。侧链液晶聚合物的相变经历两步过程：向列岛的成核和多域向列织构的形成。这种特殊的行为源于介晶的旋转取向受到聚合物主链阻碍的事实。介晶的全局分布和局部取向对于各向异性粒子的相变至关重要。此外，与 LAMMPS 中的 MD 模拟相比，我们的 GPU 加速代码比 LAMMPS 的 GPU 版本快约 4 倍，比 LAMMPS 的 CPU 版本快至少 200 倍。这项研究清楚地表明，GALAMOST 中具有 GB 潜力的 GPU 加速 MD 模拟可以有效处理具有各向异性粒子和相互作用的系统，并准确探索源自分子结构的相位差。
Gay-Berne (GB) potential is regarded as an accurate model in the simulation of anisotropic particles, especially for liquid crystal (LC) mesogens. However, its computational complexity leads to an extremely time-consuming process for large systems. Here, we developed a GPU-accelerated molecular dynamics (MD) simulation with coarse-grained GB potential implemented in GALAMOST package to investigate the LC phase transitions for mesogens in small molecules, main-chain or side-chain polymers. For identical mesogens in three different molecules, on cooling from fully isotropic melts, the small molecules form a single-domain smectic-B phase, while the main-chain LC polymers prefer a single-domain nematic phase as a result of connective restraints in neighboring mesogens. The phase transition of side-chain LC polymers undergoes a two-step process: nucleation of nematic islands and formation of multi-domain nematic texture. The particular behavior originates in the fact that the rotational orientation of the mesogenes is hindered by the polymer backbones. Both the global distribution and the local orientation of mesogens are critical for the phase transition of anisotropic particles. Furthermore, compared with the MD simulation in LAMMPS, our GPU-accelerated code is about 4 times faster than the GPU version of LAMMPS and at least 200 times faster than the CPU version of LAMMPS. This study clearly shows that GPU-accelerated MD simulation with GB potential in GALAMOST can efficiently handle systems with anisotropic particles and interactions, and accurately explore phase differences originated from molecular structures.