Efficient Density-Fitted Explicitly Correlated Dispersion and Exchange Dispersion Energies
Efficient Density-Fitted Explicitly Correlated Dispersion and Exchange Dispersion Energies
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DOI：
10.1021/acs.jctc.0c01158
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发表时间：
2021-02-19
影响因子：
5.5
通讯作者：
Patkowski, Konrad
中科院分区：
文献类型：
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作者：
Kodrycka, Monika;Patkowski, Konrad
对称适应扰动理论 (SAPT)、E-disp((20)) 和 E-exch-disp((20)) 中的前阶色散和交换色散项收敛到完全基组极限的速度缓慢。为了缓解这个问题，最近提出了这些校正的显式相关变体 E-disp((20))-F12 和 E-exch-disp((20))-F12。然而，最初的形式主义（M., Kodrycka et al., J. Chem. Theory Comput. 2019, 15, 5965-5986）虽然在提高收敛性方面非常成功，但由于需要操纵多种二电子积分，因此在计算效率方面与传统的基于轨道的 SAPT 相比并不具有竞争力。在这项工作中，我们通过使用稳健的密度拟合分解所有类型的二电子积分来消除这种需求。我们证明，当使用标准辅助碱基（例如 aug-cc-pVXZ/MP2FIT）时，密度拟合近似的误差可以忽略不计。新的实现使我们能够研究 A24 数据库中高达 aug-cc-pV5Z 的基础设置中的所有复合体，并且 E-disp((20))-F12 和 E-exch-disp((20))-F12 值比传统的对应值表现出极大改进的基础设置收敛性。在计算任何能级（SAPT0、SAPT2+3，...）的总 SAPT 相互作用能时，良好收敛的 E-disp((20))-F12 和 E-exch-disp((20))-F12 数可以替代传统的 E-disp((20)) 和 E-exch-disp((20)) 数。我们表明，添加 F12 项并不能提高低级 SAPT 处理的准确性。然而，当在 SAPT2+3(CCD)delta MP2 等高级 SAPT 方法中最小化理论误差时，由于 F12 处理而减少的基组不完整性误差大大提高了小基计算的准确性。
The leading-order dispersion and exchange-dispersion terms in symmetry-adapted perturbation theory (SAPT), E-disp((20)) and E-exch-disp((20)), suffer from slow convergence to the complete basis set limit. To alleviate this problem, explicitly correlated variants of these corrections, E-disp((20))-F12 and E-exch-disp((20))-F12, have been proposed recently. However, the original formalism (M., Kodrycka et al., J. Chem. Theory Comput. 2019, 15, 5965-5986), while highly successful in terms of improving convergence, was not competitive to conventional orbital-based SAPT in terms of computational efficiency due to the need to manipulate several kinds of two-electron integrals. In this work, we eliminate this need by decomposing all types of two-electron integrals using robust density fitting. We demonstrate that the error of the density fitting approximation is negligible when standard auxiliary bases such as aug-cc-pVXZ/MP2FIT are employed. The new implementation allowed us to study all complexes in the A24 database in basis sets up to aug-cc-pV5Z, and the E-disp((20))-F12 and E-exch-disp((20))-F12 values exhibit vastly improved basis set convergence over their conventional counterparts. The well-converged E-disp((20))-F12 and E-exch-disp((20))-F12 numbers can be substituted for conventional E-disp((20)) and E-exch-disp((20)) ones in a calculation of the total SAPT interaction energy at any level (SAPT0, SAPT2+3,...). We show that the addition of F12 terms does not improve the accuracy of low-level SAPT treatments. However, when the theory errors are minimized in high-level SAPT approaches such as SAPT2+3(CCD)delta MP2, the reduction of basis set incompleteness errors thanks to the F12 treatment substantially improves the accuracy of small-basis calculations.