Improved initial guess for minimum energy path calculations
Improved initial guess for minimum energy path calculations
复制标题
DOI：
10.1063/1.4878664
复制
发表时间：
2014-06-07
影响因子：
4.4
通讯作者：
Jonsson, Hannes
中科院分区：
文献类型：
--
作者：
Smidstrup, Soren;Pedersen, Andreas;Jonsson, Hannes
提出了一种在不计算能量的情况下，对系统给定初始状态和最终状态之间的过渡路径产生良好的初始猜测的方法。该方法利用路径上每个离散点上的两两距离的插值法构造目标函数曲面，然后利用微调弹性带方法在该目标函数曲面上寻找一条最优路径。这为例如通过从头算或密度泛函理论获得的能量表面上的最小能量路径的更密集计算提供了初始路径。IDPP表面上的最优路径比笛卡尔坐标的线性插值法更接近最小能量路径，因此，当原子在初始路径中彼此太近时，减少了达到收敛所需的迭代次数，并避免了电子结构计算中的发散。用三个例子说明了该方法：(1)乙烷分子中甲基的旋转；(2)晶体表面岛上原子的交换；(3)非晶硅中两个硅原子的交换。在所有三种情况下，通过使用IDPP路径作为初始路径，寻找具有DFT的最小能量路径的计算量减少了50%到数量级。当使用笛卡尔坐标的线性插补时，由于负载不平衡，并行计算所需的时间进一步减少。(C)2014 AIP出版有限责任公司。
A method is presented for generating a good initial guess of a transition path between given initial and final states of a system without evaluation of the energy. An objective function surface is constructed using an interpolation of pairwise distances at each discretization point along the path and the nudged elastic band method then used to find an optimal path on this image dependent pair potential (IDPP) surface. This provides an initial path for the more computationally intensive calculations of a minimum energy path on an energy surface obtained, for example, by ab initio or density functional theory. The optimal path on the IDPP surface is significantly closer to a minimum energy path than a linear interpolation of the Cartesian coordinates and, therefore, reduces the number of iterations needed to reach convergence and averts divergence in the electronic structure calculations when atoms are brought too close to each other in the initial path. The method is illustrated with three examples: (1) rotation of a methyl group in an ethane molecule, (2) an exchange of atoms in an island on a crystal surface, and (3) an exchange of two Si-atoms in amorphous silicon. In all three cases, the computational effort in finding the minimum energy path with DFT was reduced by a factor ranging from 50% to an order of magnitude by using an IDPP path as the initial path. The time required for parallel computations was reduced even more because of load imbalance when linear interpolation of Cartesian coordinates was used. (C) 2014 AIP Publishing LLC.