arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 0712.1683cond-mat.softcond-mat.mtrl-sci
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液-气界面扩散

Diffusion at the liquid-vapor interface

Daniel Duque, Pedro Tarazona, Enrique Chacón

摘要:

最近,本征采样方法已被开发,以获得,从分子模拟,在经典的毛细管波理论中假设的液-气界面的本征结构。我们在这里的目的是研究在液-气界面的动力学过程,因为这种方法可以跟踪和分析表面分子的运动,从而提供,具有很高的精度,动态信息的分子是“在”界面。我们目前的结果平行和垂直于Lennard-Jones流体的液-气界面的扩散系数,以及其他的时间和长度参数,在这个系统中的扩散过程的特征。我们还获得永久性和居留时间的统计数据。我们的结果的一般性进行测试,通过改变系统的大小和温度,对于后者的情况下,也被认为是现有的碱金属模型。我们的主要结论是,即使扩散系数仍然可以计算,周转过程,其中分子进入和离开内禀表面,是一样重要的扩散。例如,分子穿过分子直径所需的典型时间与其在表面的停留时间非常相似。

英文摘要:

Recently, the intrinsic sampling method has been developed in order to obtain, from molecular simulations, the intrinsic structure of the liquid-vapor interface that is presupposed in the classical capillary wave theory. Our purpose here is to study dynamical processes at the liquid-vapor interface, since this method allows tracking down and analyzing the movement of surface molecules, thus providing, with great accuracy, dynamical information on molecules that are "at" the interface. We present results for the coefficients for diffusion parallel and perpendicular to the liquid-vapor interface of the Lennard-Jones fluid, as well as other time and length parameters that characterize the diffusion process in this system. We also obtain statistics of permanence and residence time. The generality of our results is tested by varying the system size and the temperature; for the later case, an existing model for alkali metals is also considered. Our main conclusion is that, even if diffusion coefficients can still be computed, the turnover processes, by which molecules enter and leave the intrinsic surface, are as important as diffusion. For example, the typical time required for a molecule to traverse a molecular diameter is very similar to its residence time at the surface.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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