Can the Counterpoise Correction for Basis Set Superposition Effect Be Justified?
Can the Counterpoise Correction for Basis Set Superposition Effect Be Justified?
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DOI：
10.1021/ct400990u
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发表时间：
2014-01-01
影响因子：
5.5
通讯作者：
Baerends, E. J.
中科院分区：
文献类型：
--
作者：
Mentel, L. M.;Baerends, E. J.
基组叠加效应（BSSE）是一个简单的概念，其有效性几乎被普遍接受。平衡法也是如此，它的思想是基组偏向二聚体，因为二聚体中的每个单体都可以“使用”另一个单体上的基函数，而这在简单的单体计算中是不可能的。只有当单体和二聚体的无基组基准数可用时，才能检验该假设。我们正在测试的假设在几个系统（本文Be-2）是足够小，足够准确的基准数字（基集自由，或接近基集限制;全CI或接近全CI）是可用的或可以获得的。我们发现这个问题的答案是否定的：量子化学的标准基组似乎偏向于原子，因为二聚体的基组误差比单体大。应用平衡校正通过进一步减小单体的已经较小的基组误差来增加不平衡。平衡校正的键能比未校正的键能更偏离基组极限值。这些结论在Hartree-Fock水平和相关（CCSD（T），完全CI）水平上都成立（更强）。所以标题问题的答案是否定的。
The basis set superposition effect (BSSE) is a simple concept, and its validity is almost universally accepted. So is the counterpoise method to correct for it. The idea is that the basis set is biased toward the dimer because each monomer in the dimer can "use" the basis functions on the other monomer, which it cannot in a simple monomer calculation. This hypothesis can only be tested if basis set free benchmark numbers are available for monomers and dimer. We are testing the hypothesis on a few systems (in this paper Be-2) that are small enough that sufficiently accurate benchmark numbers (basis set free, or close to basis set limit; full CI or close to full Cl) are available or can be obtained. We find that the answer to the title question is negative: the standard basis sets of quantum chemistry appear to be biased toward the atom in the sense that basis set errors are larger for the dimer than the monomer. Applying the counterpoise correction increases the imbalance by reducing the already smaller basis set error of the monomer even further. Counterpoise corrected bond energies then deviate more from the basis set limit numbers than uncorrected bond energies. These conclusions hold both at the Hartree-Fock level and (much stronger) at the correlated (CCSD(T), full CI) levels. So the answer to the title question is No.