Department of Chemistry, College of Sciences, Shanghai University, 99 Shangda Road, Shanghai 200444, China.
J Chem Phys. 2009 Dec 14;131(22):224901. doi: 10.1063/1.3271829.
Intermolecular momentum transfer in methanol-water mixture solvated poly(perfluoro-sulfonic acid) membrane is studied in terms of center of mass velocity cross-correlation functions between molecular mass centers in their first coordination shells based on molecular dynamics simulations. Moreover, the center of mass velocity cross-correlation functions are also decomposed into longitudinal and transversal contributions. The fastest momentum transfer is observed between hydronium cation and water molecule due to the strong hydrogen bond interaction. The center of mass velocity cross-correlation functions reach peak value in about 36 fs, corresponding to a single collision with a neighboring molecule. For the momentum transfer between the water molecule and methanol molecule, the peaking time is 70 fs or about twice of that between hydronium cation and water molecule. Oscillation of the center of mass velocity cross-correlation functions between hydronium cation and water molecule is also observed due to the cage effect in their equilibrium positions.
基于分子动力学模拟，通过第一配位壳中分子质心之间的质心速度互相关函数研究甲醇-水混合物溶剂化聚（全氟磺酸）膜中的分子间动量传递。此外，质心速度互相关函数也被分解为纵向和横向贡献。由于强氢键相互作用，观察到在质子化铵阳离子和水分子之间的最快动量传递。质心速度互相关函数在约 36 fs 达到峰值，对应于与相邻分子的单次碰撞。对于水分子和甲醇分子之间的动量传递，达到峰值的时间为 70 fs，大约是质子化铵阳离子和水分子之间的两倍。由于在平衡位置的笼效应，质子化铵阳离子和水分子之间的质心速度互相关函数也观察到了振动。
