Bobbitt N Scott, Schofield Grady, Lena Charles, Chelikowsky James R
Department of Chemical Engineering, The University of Texas at Austin, Austin, Texas 78712, USA.
Center for Computational Materials, Institute for Computational Engineering and Sciences, The University of Texas at Austin, Austin, Texas 78712, USA.
Phys Chem Chem Phys. 2015 Dec 21;17(47):31542-9. doi: 10.1039/c5cp02561c.
Real space pseudopotentials have a number of advantages in solving for the electronic structure of materials. These advantages include ease of implementation, implementation on highly parallel systems, and great flexibility for describing partially periodic systems. One limitation of this approach, shared by other electronic structure methods, is the slow convergence of interatomic forces when compared to total energies. For real space methods, this requires a fine grid to converge a solution of the Kohn-Sham problem, which is accompanied by concurrent increase in memory and additional matrix-vector multiplications. Here we introduce a method to expedite the computation of interatomic forces by employing a high order integration technique. We demonstrate the usefulness of this technique by calculating accurate bond lengths and vibrational frequencies for molecules and nanocrystals without using fine real space grids.
实空间赝势在求解材料的电子结构方面具有诸多优势。这些优势包括易于实现、可在高度并行系统上实现以及在描述部分周期性系统时具有很大的灵活性。与其他电子结构方法一样，这种方法的一个局限性是，与总能相比，原子间力的收敛速度较慢。对于实空间方法，这需要一个精细的网格来收敛Kohn-Sham问题的解，这会同时导致内存增加和额外的矩阵-向量乘法。在这里，我们介绍一种通过采用高阶积分技术来加速原子间力计算的方法。我们通过在不使用精细实空间网格的情况下计算分子和纳米晶体的精确键长和振动频率，证明了该技术的实用性。
