Electrostatic interactions in finite systems treated with periodic boundary conditions: Application to linear-scaling density functional theory
Electrostatic interactions in finite systems treated with periodic boundary conditions: Application to linear-scaling density functional theory
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DOI：
10.1063/1.3662863
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发表时间：
2011-11-28
影响因子：
4.4
通讯作者：
Skylaris, Chris-Kriton
中科院分区：
文献类型：
--
作者：
Hine, Nicholas D. M.;Dziedzic, Jacek;Skylaris, Chris-Kriton
在密度泛函理论(DFT)中，比较了在周期边界条件(PBC)内处理有限孤立系统静电相互作用的方法，特别是线性标度(LS)DFT。通常，PBC在物理上是不现实的，但它是基组选择和使用傅立叶变换计算Hartree势的有效性的不可避免的结果。在这种情况下，需要避免PBC对计算的影响，以便得到的结果代表开放边界而不是周期边界。LS-DFT中遇到的非常大的系统使得孤立系统的超胞近似的要求更难管理，我们展示了一些情况，其中开放边界(无穷大胞元)的结果不能从不断增大的周期胞元的计算外推得到。我们讨论、实现和测试了三种非常不同的方法来克服或绕过PBC的影响：截断库仑相互作用结合模拟单元的填充、基于最小图像约定的方法以及显式使用开放边界条件(OBC)。我们已经在ONETEP LS-DFT计划中实现了这些方法，并将它们应用于一系列系统，包括极性纳米棒和蛋白质。我们将其精度、复杂性和收敛速度与模拟单元大小进行了比较。我们证明，与纯OBC方法相比，PBCS中的校正方法可以更有效、更准确地实现OBC结果。(C)2011年美国物理研究所。[DOI：10.1063/1.3662863]
We present a comparison of methods for treating the electrostatic interactions of finite, isolated systems within periodic boundary conditions (PBCs), within density functional theory (DFT), with particular emphasis on linear-scaling (LS) DFT. Often, PBCs are not physically realistic but are an unavoidable consequence of the choice of basis set and the efficacy of using Fourier transforms to compute the Hartree potential. In such cases the effects of PBCs on the calculations need to be avoided, so that the results obtained represent the open rather than the periodic boundary. The very large systems encountered in LS-DFT make the demands of the supercell approximation for isolated systems more difficult to manage, and we show cases where the open boundary (infinite cell) result cannot be obtained from extrapolation of calculations from periodic cells of increasing size. We discuss, implement, and test three very different approaches for overcoming or circumventing the effects of PBCs: truncation of the Coulomb interaction combined with padding of the simulation cell, approaches based on the minimum image convention, and the explicit use of open boundary conditions (OBCs). We have implemented these approaches in the ONETEP LS-DFT program and applied them to a range of systems, including a polar nanorod and a protein. We compare their accuracy, complexity, and rate of convergence with simulation cell size. We demonstrate that corrective approaches within PBCs can achieve the OBC result more efficiently and accurately than pure OBC approaches. (C) 2011 American Institute of Physics. [doi:10.1063/1.3662863]