Molecular dynamics simulation of semi-flexible mesogens
Molecular dynamics simulation of semi-flexible mesogens
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半柔性介晶的分子动力学模拟
DOI：
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发表时间：
1994
期刊：
影响因子：
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通讯作者：
M. Wilson
中科院分区：
文献类型：
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作者：
M. Wilson
分子动力学模拟系统的半柔性模型介晶组成的七个切向硬球。模拟采用的“摇铃球”的方法，原子网站被限制在狭窄的潜在威尔斯，自由飞行的分子动力学之间发生弹性碰撞的领域。研究了四种不同成键约束体系的相图。研究发现，向硬球链中添加少量分子柔性会增加各向同性向列相转变发生的密度。然而，太多的灵活性完全破坏了稳定阶段。在高密度下，最刚性的系统形成近晶-A相，并且有强有力的证据表明，在近晶层本身的密度附近的流体-固体过渡的顺序。也有证据表明，增加分子的灵活性，推动固相的形成，以更高的密度。计算器
Molecular dynamics simulations are reported for systems of semi-flexible model mesogens composed of seven tangential hard spheres. The simulations employ the ‘rattling spheres’ approach whereby atomic sites are constrained to lie within narrow potential wells, with free-flight molecular dynamics occurring in between elastic collisions of spheres. The phase diagams of four systems with different bonding constraints have been studied. It is found that the addition of a small amount of molecular flexibility to the chains of hard spheres increases the density at which the isotropic to nematic phase transition takes place. Too much flexibility however destroys the nematic phase completely. At high density the most rigid of the systems forms a smectic-A phase and there is strong evidence for ordering within the smectic layers themselves at densities near the fluid-solid transition. There is also evidence that increasing molecular flexibility pushes the formation of the solid phase to higher densities. Calculati...