Zhang Huan, Qiu Lili, Hu Dan
Zhiyuan College and Institute of Natural Sciences, Shanghai Jiao Tong University, Shanghai 200240, China.
School of Mathematical Sciences, Institute of Natural Sciences, and MOE-LSC, Shanghai Jiao Tong University, Shanghai 200240, China.
J Comput Chem. 2019 Jul 5;40(18):1701-1706. doi: 10.1002/jcc.25824. Epub 2019 Mar 20.
The dimer method and its variants have been shown to be efficient in finding saddle points on potential surfaces. In the dimer method, the most unstable direction is approximately obtained by minimizing the total potential energy of the dimer. Then, the force in this direction is reversed to move the dimer toward saddle points. When the finite-temperature effect is important for a high-dimensional system, one usually needs to describe the dynamics in a low-dimensional space of reaction coordinates. In this case, transition states are collected as saddle points on the free energy surface. The traditional dimer method cannot be directly employed to find saddle points on a free energy surface since the surface is not known a priori. Here, we develop a finite-temperature dimer method for searching saddle points on the free energy surface. In this method, a constrained rotation dynamics of the dimer system is used to sample dimer directions and an efficient average method is used to obtain a good approximation of the most unstable direction. This approximated direction is then used in reversing the force component and evolving the dimer toward saddle points. Our numerical results suggest that the new method is efficient in finding saddle points on free energy surfaces. © 2019 Wiley Periodicals, Inc.
二聚体方法及其变体已被证明在寻找势能面上的鞍点方面是有效的。在二聚体方法中，最不稳定方向大约是通过最小化二聚体的总势能来获得的。然后，在这个方向上的力被反向，以使二聚体朝着鞍点移动。当有限温度效应对于高维系统很重要时，通常需要在反应坐标的低维空间中描述动力学。在这种情况下，过渡态作为自由能面上的鞍点被收集起来。由于自由能面事先未知，传统的二聚体方法不能直接用于寻找自由能面上的鞍点。在这里，我们开发了一种用于在自由能面上搜索鞍点的有限温度二聚体方法。在这种方法中，二聚体系统的约束旋转动力学用于对二聚体方向进行采样，并且使用一种有效的平均方法来获得最不稳定方向的良好近似。然后，这个近似方向被用于反向力分量并使二聚体朝着鞍点演化。我们的数值结果表明，新方法在寻找自由能面上的鞍点方面是有效的。© 2019威利期刊公司。
