Dipartimento di Scienze Chimiche, via Marzolo 1, 35131 Padova, Italy.
Phys Chem Chem Phys. 2018 Dec 19;21(1):104-113. doi: 10.1039/c8cp06106h.
Recent nonequilibrium Molecular Dynamics (NEMD) simulations revealed preferential orientation, induced by a temperature gradient, in fluids of uncharged dumbbell-like particles. The magnitude of this phenomenon, called thermo-orientation, was found to be linear in the applied temperature gradient and to increase with the difference in shape or mass between the two beads of the particles. The underlying mechanism and the microscopic determinants of the phenomenon are not obvious. Here, after examination of the general symmetry requirements for thermo-orientation, we have extended the NEMD simulations to uncharged particles of various shapes and mass distribution, including chiral cases. The numerical results are rationalized by a microscopic model, based on the assumption of local equilibrium. This allows us to correlate the thermo-orientation response of arbitrarily shaped particles to quantities that characterize their shape and mass distribution.
最近的非平衡分子动力学（NEMD）模拟揭示了在不带电的哑铃状粒子流体中，由温度梯度引起的优先取向。这种现象的大小，称为热取向，被发现与施加的温度梯度呈线性关系，并随着粒子的两个珠子之间的形状或质量差异的增加而增加。该现象的潜在机制和微观决定因素尚不清楚。在这里，在检查了热取向的一般对称要求之后，我们将 NEMD 模拟扩展到了各种形状和质量分布的不带电粒子，包括手性情况。基于局部平衡的假设，通过微观模型对数值结果进行了合理化处理。这使我们能够将任意形状的粒子的热取向响应与表征其形状和质量分布的量相关联。
