Structure and Dynamics of Acetonitrile Confined in a Silica Nanopore
Structure and Dynamics of Acetonitrile Confined in a Silica Nanopore
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DOI：
10.1021/jp301007k
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发表时间：
2012-05-03
影响因子：
3.7
通讯作者：
Berne, B. J.
中科院分区：
文献类型：
--
作者：
Cheng, Liwen;Morrone, Joseph A.;Berne, B. J.
通过分子动力学模拟研究了乙腈在不同官能度的二氧化硅纳米孔中的吸附行为。通过第一性原理分子动力学模拟，表面和液体之间的氢键相互作用被参数化。结果发现，乙腈订单成双层结构附近的表面，与以前的模拟和实验。本文提出了一种新的方法来计算孔内不同层中分子的时间相关函数。这种方法考虑到了层中分子的短寿命。我们比较这种方法与以前的技术，不考虑这个生命周期，并讨论他们的陷阱。我们表明，在协议与实验中，系统的动力学可以描述的两个人口模型，占散装样放松中心和附近的孔隙表面的动力学受挫。发现特定的氢键相互作用在产生这种行为中起着重要作用。
Acetonitrile confined in silica nanopores with surfaces of varying functionality is studied by means of molecular dynamics simulation. The hydrogen-bonding interaction between the surface and the liquid is parametrized by means of first-principles molecular dynamics simulations. It is found that acetonitrile orders into bilayer like structures near the surface, in agreement with prior simulations and experiments. A newly developed method is applied to calculate relevant time correlation functions for molecules in different layers of the pore. This method takes into account the short lifetimes of the molecules in the layers. We compare this method with prior techniques that do not take this lifetime into account and discuss their pitfalls. We show that in agreement with experiment, the dynamics of the system may be described by a two population model that accounts for bulk-like relaxation in the center and frustrated dynamics near the surface of the pore. Specific hydrogen-bonding interactions are found to play a large role in engendering this behavior.