Incorporation of quantum mechanical electronic structure data is necessary to properly capture the physics of many chemical processes. Proton hopping in water, which involves rearrangement of chemical and hydrogen bonds, is one such example of an inherently quantum mechanical process. Standard ab initio molecular dynamics (AIMD) methods, however, do not yet accurately predict the structure of water and are therefore less than optimal for developing force fields. We have instead utilized a recently developed method which minimally biases AIMD simulations to match limited experimental data to develop novel multiscale reactive molecular dynamics (MS-RMD) force fields by using relative entropy minimization. In this paper, we present two new MS-RMD models using such a parameterization: one which employs water with harmonic internal vibrations and another which uses anharmonic water. We show that the newly developed MS-RMD models very closely reproduce the solvation structure of the hydrated excess proton in the target AIMD data. We also find that the use of anharmonic water increases proton hopping, thereby increasing the proton diffusion constant.

中文翻译：

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使用从头算分子动力学模拟开发反作用力场的方法对实验数据的影响最小

合并量子机械电子结构数据对于正确捕获许多化学过程的物理过程是必不可少的。水中的质子跳变涉及化学和氢键的重排，是固有的量子力学过程的这种例子之一。标准从头算但是，分子动力学（AIMD）方法尚不能准确预测水的结构，因此对于发展力场而言还不是最佳方法。我们取而代之的是利用一种最近开发的方法，该方法将AIMD模拟值最小化以匹配有限的实验数据，从而通过使用相对熵最小化来开发新颖的多尺度反应分子动力学（MS-RMD）力场。在本文中，我们介绍了使用这种参数化的两个新的MS-RMD模型：一个使用具有谐波内部振动的水，另一个使用非谐波水。我们显示，新开发的MS-RMD模型非常接近地在目标AIMD数据中重现了水合过量质子的溶剂化结构。我们还发现使用非调和水会增加质子跳跃，从而增加质子扩散常数。