MTA-BME Lendület Quantum Chemistry Research Group, Department of Physical Chemistry and Materials Science , Budapest University of Technology and Economics , P.O. Box 91, H-1521 Budapest , Hungary.
J Chem Theory Comput. 2018 Aug 14;14(8):4193-4215. doi: 10.1021/acs.jctc.8b00442. Epub 2018 Jul 24.
An optimized implementation of the local natural orbital (LNO) coupled-cluster (CC) with single-, double-, and perturbative triple excitations [LNO-CCSD(T)] method is presented. The integral-direct, in-core, highly efficient domain construction technique of our local second-order Møller-Plesset (LMP2) scheme is extended to the CC level. The resulting scheme, which is also suitable for general-order LNO-CC calculations, inherits the beneficial properties of the LMP2 approach, such as the asymptotically linear-scaling operation count, the asymptotically constant data storage requirement, and the completely independent domain calculations. In addition to integrating our recent redundancy-free LMP2 and Laplace-transformed (T) algorithms with the LNO-CCSD(T) code, the memory demand, the domain and LNO construction, the auxiliary basis compression, and the previously rate-determining two-external integral transformation have been significantly improved. The accuracy of all of the approximations is carefully examined on medium-sized to large systems to determine reasonably tight default truncation thresholds. Our benchmark calculations, performed on molecules of up to 63 atoms, show that the optimized method with the default settings provides average correlation and reaction energy errors of less than 0.07% and 0.34 kcal/mol, respectively, compared to the canonical CCSD(T) reference. The efficiency of the present LNO-CCSD(T) implementation is demonstrated on realistic, three-dimensional examples. Using the new code, an LNO-CCSD(T) correlation energy calculation with a triple-ζ basis set is feasible on a single processor for a protein molecule including 2380 atoms and more than 44000 atomic orbitals.
本文提出了一种优化的局部自然轨道（LNO）耦合簇（CC）与单、双和微扰三重激发[LNO-CCSD（T）]方法的实现。我们局部二阶 Møller-Plesset（LMP2）方案的积分-直接、核内、高效域构造技术被扩展到 CC 水平。该方案也适用于一般阶 LNO-CC 计算，继承了 LMP2 方法的有益特性，例如渐近线性标度的操作计数、渐近常数数据存储要求以及完全独立的域计算。除了将我们最近的无冗余 LMP2 和拉普拉斯变换（T）算法与 LNO-CCSD（T）代码集成之外，内存需求、域和 LNO 构造、辅助基压缩以及以前的速率决定的两个外部积分变换都得到了显著改进。在中等大小到较大的系统上仔细检查了所有近似的准确性，以确定合理的严格默认截断阈值。我们在分子多达 63 个原子的基准计算中表明，与规范 CCSD（T）参考相比，优化的方法默认设置提供了小于 0.07%和 0.34 kcal/mol 的平均相关和反应能量误差。在实际的三维示例中展示了本 LNO-CCSD（T）实现的效率。使用新代码，在单个处理器上使用三重-ζ基组进行 LNO-CCSD（T）相关能量计算对于包含 2380 个原子和超过 44000 个原子轨道的蛋白质分子是可行的。
