Maurer Simon A, Clin Lucien, Ochsenfeld Christian
Chair of Theoretical Chemistry, Department of Chemistry, University of Munich (LMU), Butenandtstr. 7, D-81377 Munich, Germany and Center for Integrated Protein Science (CIPSM) at the Department of Chemistry, University of Munich (LMU), Butenandtstr. 5-13, D-81377 Munich, Germany.
J Chem Phys. 2014 Jun 14;140(22):224112. doi: 10.1063/1.4881144.
Our recently developed QQR-type integral screening is introduced in our Cholesky-decomposed pseudo-densities Møller-Plesset perturbation theory of second order (CDD-MP2) method. We use the resolution-of-the-identity (RI) approximation in combination with efficient integral transformations employing sparse matrix multiplications. The RI-CDD-MP2 method shows an asymptotic cubic scaling behavior with system size and a small prefactor that results in an early crossover to conventional methods for both small and large basis sets. We also explore the use of local fitting approximations which allow to further reduce the scaling behavior for very large systems. The reliability of our method is demonstrated on test sets for interaction and reaction energies of medium sized systems and on a diverse selection from our own benchmark set for total energies of larger systems. Timings on DNA systems show that fast calculations for systems with more than 500 atoms are feasible using a single processor core. Parallelization extends the range of accessible system sizes on one computing node with multiple cores to more than 1000 atoms in a double-zeta basis and more than 500 atoms in a triple-zeta basis.
我们最近开发的QQR型积分筛选方法被引入到我们的二阶Møller-Plesset微扰理论的Cholesky分解伪密度（CDD-MP2）方法中。我们将单位分解（RI）近似与采用稀疏矩阵乘法的高效积分变换相结合。RI-CDD-MP2方法显示出随着系统规模呈渐近立方缩放行为，且前置因子较小，这导致在小基组和大基组情况下都能较早地过渡到传统方法。我们还探索了局部拟合近似的使用，这使得对于非常大的系统可以进一步降低缩放行为。我们的方法的可靠性在中等规模系统的相互作用和反应能量测试集上以及在我们自己的大系统总能量基准集中的各种选择上得到了证明。对DNA系统的计时表明，使用单个处理器核心对具有500多个原子的系统进行快速计算是可行的。并行化将具有多个核心的一个计算节点上可访问的系统规模范围扩展到双ζ基下超过1000个原子和三ζ基下超过500个原子。
