Lesiuk Michał
Faculty of Chemistry, University of Warsaw, Pasteura 1, 02-093 Warsaw, Poland.
J Chem Phys. 2020 Jan 31;152(4):044104. doi: 10.1063/1.5129883.
We present a simple method for a posteriori removal of a significant fraction of the density-fitting error from the calculated total coupled-cluster energies. The method treats the difference between the exact and density-fitted integrals as a perturbation, and simplified response-like equations allow us to calculate improved amplitudes and the corresponding energy correction. The proposed method is tested at the coupled-cluster singles and doubles level of theory for a diverse set of moderately-sized molecules. On average, error reductions by a factor of approximately 10 and 20 are observed in double-zeta and triple-zeta basis sets, respectively. Similar reductions are observed in calculations of interaction energies of several model complexes. The computational cost of the procedure is small in comparison with the preceding coupled-cluster iterations. The applicability of this method is not limited to the density-fitting approximation; in principle, it can be used in conjunction with an arbitrary decomposition scheme of the electron repulsion integrals.
我们提出了一种简单的方法，用于从计算得到的总耦合簇能量中后验去除很大一部分密度拟合误差。该方法将精确积分与密度拟合积分之间的差异视为微扰，简化的类似响应方程使我们能够计算改进的振幅和相应的能量校正。所提出的方法在耦合簇单双激发理论水平上针对各种中等规模分子进行了测试。平均而言，在双ζ和三ζ基组中分别观察到误差降低了约10倍和20倍。在几个模型复合物的相互作用能计算中也观察到了类似的降低。与之前的耦合簇迭代相比，该过程的计算成本较小。该方法的适用性不限于密度拟合近似；原则上，它可与电子排斥积分的任意分解方案结合使用。
