论文标题
基于Voronoi Tessellation的扭转势能表面的近似重建
Approximate Reconstruction of Torsional Potential Energy Surface based on Voronoi Tessellation
论文作者
论文摘要
含有各种官能团的复杂分子中的扭转模式通常是强烈的耦合，因此谐波近似和一维扭转处理是不准确评估其分区功能的。近年来，已经提出并应用了一种多结构近似方法来处理扭转的非谐度。但是，这些方法将确切的“几乎周期性”势能近似，以概述具有对称屏障位置和高度的局部周期函数。在目前的理论研究中，我们说明当扭转模式呈现不均匀分布的局部最小值时，近似值是不准确的。因此，我们提出了一种改进的方法，通过使用局部最小值及其voronoi tessellation的信息来重建近似潜力，以替代周期性。首先，我们通过引入两个周期性参数来建立不对称的屏障高度，并假设确切的屏障位置位于Voronoi细胞的边界。其次，我们使用多重加权的Voronoi Tessellation通过定义与结构相关的距离度量来完善屏障高度和位置。该提出的方法已针对一些较高维度的情况进行了测试，所有这些方法均显示出有望提高的准确性。
Torsional modes within a complex molecule containing various functional groups are often strongly coupled so that the harmonic approximation and one-dimensional torsional treatment are inaccurate to evaluate their partition functions. A family of multi-structural approximation methods have been proposed and applied in recent years to deal with the torsional anharmonicity.However, these methods approximate the exact "almost periodic" potential energy as a summation of local periodic functions with symmetric barrier positions and heights. In the present theoretical study, we illustrated that the approximation is inaccurate when torsional modes present non-uniformly distributed local minima. Thereby, we proposed an improved method to reconstruct approximate potential to replace the periodic potential by using information of the local minima and their Voronoi tessellation. First, we established asymmetric barrier heights by introducing two periodicity parameters and assuming that the exact barrier positions are at the boundaries of Voronoi cells. Second, we used multiplicatively weighted Voronoi tessellation to refine the barrier heights and positions by defining a structure-related distance metric. The proposed method has been tested for a few higher-dimensional cases, all of which show promising improved accuracy.
