Orbital-optimized MP2.5 and its analytic gradients: Approaching CCSD(T) quality for noncovalent interactions
Orbital-optimized MP2.5 and its analytic gradients: Approaching CCSD(T) quality for noncovalent interactions
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DOI：
10.1063/1.4902226
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发表时间：
2014-11-28
影响因子：
4.4
通讯作者：
Sherrill, C. David
中科院分区：
文献类型：
--
作者：
Bozkaya, Ugur;Sherrill, C. David
提出了轨道优化 MP2.5 [或简称“优化 MP2.5”，简称 OMP2.5] 及其解析能量梯度。该方法的成本与用于能量计算的耦合簇单打和双打 (CCSD) [O(N-6) 缩放] 的成本一样多。然而，对于解析梯度计算，OMP2.5 方法的成本仅为 CCSD 的一半，因为无需求解 OMP2.5 的 lambda(2) 振幅方程。将 OMP2.5 方法的性能与标准二阶 Moller-Plesset 微扰理论 (MP2)、MP2.5、CCSD 以及带有微扰三元组的耦合簇单簇和双簇 (CCSD(T)) 方法的平衡几何、自由基之间的氢转移反应和非共价相互作用进行了比较。对于闭壳和开壳分子的键长，使用 Dunning 的 cc-pCVQZ 基组，OMP2.5 方法比 MP2.5 和 CCSD 分别提高了 38%-43% 和 31%-28%。对于氢转移反应能量的完整基集（CBS）预测，OMP2.5方法表现出明显优于MP2.5的性能，平均绝对误差为1.1 kcal mol(-1)，比MP2.5（11.8 kcal mol(-1)）低10倍以上，与MP2（14.6 kcal mol（-1））相比，低12倍以上。减少错误。对于非共价相互作用能（在 CBS 限制下），OMP2.5 方法在闭壳系统中保持了 MP2.5 的良好性能，而对于开壳系统，它的性能显着优于 MP2.5 和 CCSD，并接近 CCSD(T) 质量。当优化轨道用于开壳非共价相互作用时，MP2.5 误差减少了 5 倍，与 CCSD 相比，误差减少了 3 倍以上。总体而言，目前的应用结果表明，OMP2.5 方法对于开壳层非共价相互作用和其他具有困难电子结构的化学系统非常有前景。 (C) 2014 AIP 出版有限责任公司。
Orbital-optimized MP2.5 [or simply "optimized MP2.5," OMP2.5, for short] and its analytic energy gradients are presented. The cost of the presented method is as much as that of coupled-cluster singles and doubles (CCSD) [O(N-6) scaling] for energy computations. However, for analytic gradient computations the OMP2.5 method is only half as expensive as CCSD because there is no need to solve lambda(2)-amplitude equations for OMP2.5. The performance of the OMP2.5 method is compared with that of the standard second-order Moller-Plesset perturbation theory (MP2), MP2.5, CCSD, and coupled-cluster singles and doubles with perturbative triples (CCSD(T)) methods for equilibrium geometries, hydrogen transfer reactions between radicals, and noncovalent interactions. For bond lengths of both closed and open-shell molecules, the OMP2.5 method improves upon MP2.5 and CCSD by 38%-43% and 31%-28%, respectively, with Dunning's cc-pCVQZ basis set. For complete basis set (CBS) predictions of hydrogen transfer reaction energies, the OMP2.5 method exhibits a substantially better performance than MP2.5, providing a mean absolute error of 1.1 kcal mol(-1), which is more than 10 times lower than that of MP2.5 (11.8 kcal mol(-1)), and comparing toMP2 (14.6 kcal mol(-1)) there is a more than 12-fold reduction in errors. For noncovalent interaction energies (at CBS limits), the OMP2.5 method maintains the very good performance of MP2.5 for closed-shell systems, and for open-shell systems it significantly outperforms MP2.5 and CCSD, and approaches CCSD(T) quality. The MP2.5 errors decrease by a factor of 5 when the optimized orbitals are used for open-shell noncovalent interactions, and comparing to CCSD there is a more than 3-fold reduction in errors. Overall, the present application results indicate that the OMP2.5 method is very promising for open-shell noncovalent interactions and other chemical systems with difficult electronic structures. (C) 2014 AIP Publishing LLC.