Goldey Matthew, Head-Gordon Martin
Department of Chemistry, University of California, Berkeley, California 94720, United States.
Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States.
J Phys Chem Lett. 2012 Dec 6;3(23):3592-8. doi: 10.1021/jz301694b. Epub 2012 Nov 27.
Second-order Møller-Plesset perturbation theory (MP2) treats electron correlation at low computational cost, but suffers from basis set superposition error (BSSE) and fundamental inaccuracies in long-range contributions. The cost differential between complete basis set (CBS) and small basis MP2 restricts system sizes where BSSE can be removed. Range-separation of MP2 could yield more tractable and/or accurate forms for short- and long-range correlation. Retaining only short-range contributions proves to be effective for MP2 in the small aug-cc-pVDZ (aDZ) basis. Using one range-separation parameter, superior behavior is obtained versus both MP2/aDZ and MP2/CBS for inter- and intramolecular test sets. Attenuation of the long-range helps to cancel both BSSE and intrinsic MP2 errors. Direct scaling of the MP2 correlation energy proves useful as well. The resulting SMP2/aDZ, MP2(erfc, aDZ), and MP2(terfc, aDZ) methods perform far better than MP2/aDZ across systems with hydrogen-bonding, dispersion, and mixed interactions at a fraction of MP2/CBS computational cost.
二阶莫勒-普莱塞特微扰理论（MP2）以较低的计算成本处理电子相关，但存在基组叠加误差（BSSE）以及长程贡献中的基本不准确性。完全基组（CBS）和小基组MP2之间的成本差异限制了能够消除BSSE的系统规模。MP2的范围分离可以为短程和长程相关产生更易于处理和/或更准确的形式。在小的aug-cc-pVDZ（aDZ）基组中，仅保留MP2的短程贡献被证明是有效的。使用一个范围分离参数，对于分子间和分子内测试集，相对于MP2/aDZ和MP2/CBS都能获得更好的性能。长程的衰减有助于消除BSSE和MP2的固有误差。MP2相关能的直接缩放也被证明是有用的。由此产生的SMP2/aDZ、MP2(erfc, aDZ)和MP2(terfc, aDZ)方法在具有氢键、色散和混合相互作用的系统中，以MP2/CBS计算成本的一小部分，表现远优于MP2/aDZ。
