论文标题
在被动或主动刺激下模拟超冷水
Simulations of supercooled water under passive or active stimuli
论文作者
论文摘要
我们使用分子动力学模拟来研究受稀释的偶氮苯疏水探针受到不同刺激的超冷水的行为。当分子电动机不折叠时，它充当被动探针，修饰周围的水结构，而当电动机活跃时，它会诱导主要作用于动力学上的介质内部的基本扩散过程。我们研究了两种特定的密度，即环境水的密度和周围的环境压力密度较低，分别选择有利于高密度液体和低密度液体（LDL）水。我们发现，被动探针会导致加速度或在其周围的扩散过程减慢，具体取决于水的密度，而主动探针仅诱导加速。 我们发现在被动探针附近的两个密度的扩散系数之间，在t = 215 k之间进行了交叉。这种动态交叉与探针附近水结构的修饰有关。结构计算显示LDL水比例在相同温度周围的比例，这表明它诱导了观察到的动态交叉。与这些结果相反，主动刺激增加了密度的扩散，并在低温下降低了LDL水的比例。但是，我们还发现，对于活跃的刺激，两种研究密度之间的LDL比例的交叉分频器显示了主动刺激和被动刺激结果之间的显着相似性。
We use molecular dynamics simulations to study the behavior of supercooled water subject to different stimuli from a diluted azobenzene hydrophobic probe. When the molecular motor does not fold, it acts as a passive probe, modifying the structure of water around it, while when the motor is active, it induces elementary diffusion processes inside the medium acting mainly on the dynamics. We study two particular densities, the density of ambient water and a lower density around the ambient pressure ice density, chosen to favor high density liquid and low density liquid (LDL) water, respectively. We find that the passive probe induces ever an acceleration or a slowing down of the diffusion process around it depending on the density of water, while the active probe induces acceleration only. We find a crossover between the diffusion coefficients for the two densities near the passive probe, around T = 215 K. This dynamical crossover is associated with a modification of the structure of water near the probe. Structure calculations show a crossover of the proportion of LDL water around the same temperature, suggesting that it induces the observed dynamical crossover. In opposition with these results, the active stimuli increase diffusion for both densities and decrease the proportion of LDL water at low temperatures. However, we also find for the active stimuli a crossover of the LDL proportion between the two densities of study, showing remarkable similarities between active and passive stimulus results.
