Methods of the explicitly correlated F12 approach are applied to the problem of calculating the uncoupled second-order dispersion energy in symmetry-adapted perturbation theory. The accuracy of the new method is tested for noncovalently bound complexes from the A24 data set [J. Řezáč and P. Hobza, J. Chem. Theory Comput.2013, 9, 2151] using standard orbital basis sets aug-cc-pVXZ supplemented with auxiliary aug-cc-pVXZ_OPTRI sets. For near equilibrium geometries, it is possible to recover the dispersion energy with average relative errors consistently smaller than 0.1% (with respect to the CBS extrapolated limit estimated from regular orbital calculations). This level of accuracy is achieved already in the basis set of a triple-ζ quality, when a Slater-type correlation factor exp(−0.9r₁₂) is combined with variant C of the F12 approach. The explicitly correlated approach clearly outperforms regular orbital calculations in the basis set of quintuple-ζ quality (average relative errors of 1%).

中文翻译：

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基于显式相关F12方法的适应对称性摄动理论的色散能

显式相关的F12方法的方法适用于对称自适应扰动理论中计算未耦合二阶色散能量的问题。对于A24数据集中非共价结合的复合物，测试了该新方法的准确性[J. Řezáč和P.Hobza，《化学杂志》理论计算。2013，9，2151]使用标准的轨道基组AUG-CC-PV X ž补充有辅助AUG-CC-PV XZ_OPTRI集。对于接近平衡的几何形状，有可能以平均相对误差始终小于0.1％（相对于根据常规轨道计算估算出的CBS外推极限）恢复色散能量。当将Slater型相关因子exp（-0.9 r ₁₂）与F12方法的变体C相结合时，这种精度水平已经在三重ζ质量的基础上实现。在五元组-ζ质量（平均相对误差为1％）的基础集中，显式相关的方法明显胜过常规的轨道计算。