Basis set and correlation dependent extrapolation of correlation energy
Basis set and correlation dependent extrapolation of correlation energy
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DOI：
10.1063/1.1534091
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发表时间：
2003-01
影响因子：
4.4
通讯作者：
Soon Bum Huh;Jae Shin Lee
中科院分区：
文献类型：
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作者：
Soon Bum Huh;Jae Shin Lee
根据基组质量和相关水平的不同，通过改变参数γ，设计了一个简单的（X+γ）-3的外推公式，将相关能量与相关一致的（aug-）cc-pVXZ和（aug-）cc-pV（X+1）Z[X=D（2），T（3），Q（4）]基组拟合，以估计基组极限.给出了适用于二阶Moller-Plesset微扰理论和单、双激发耦合团簇理论的显式外推公式，并应用于各种氢键和货车德瓦耳斯团簇的基组极限结合能的估算。将该公式的结果与参考基组极限结果和其他外推方法的结果进行了比较，结果表明，本文提出的外推公式即使在小基组下也能得到可靠的基组极限估计，可有效地用于研究大的弱束缚复合物.
A simple extrapolation formula of (X+γ)−3 which fits correlation energies with correlation consistent (aug-)cc-pVXZ and (aug-)cc-pV(X+1)Z[X=D(2),T(3),Q(4)] basis sets to estimate the basis set limit was devised by varying the parameter γ according to basis set quality and correlation level. The explicit extrapolation formulas suitable for calculations at the second order Moller–Plesset perturbation theory and single and double excitation coupled cluster theory with perturbative triples correction level are presented and applications are made to estimate the basis set limit binding energies of various hydrogen-bonded and van der Waals clusters. A comparison of the results by this formula with the reference basis set limit results and the results by other extrapolation methods reveals that the extrapolation formulas proposed here can yield the reliable basis set limit estimates even with the small basis sets and could be used effectively for investigating large weakly bound complexes.