Jacquemin Denis, Femenias Antoine, Chermette Henry, Ciofini Ilaria, Adamo Carlo, André Jean-Marie, Perpète Eric A
Laboratoire de Chimie Théorique Appliquée, Facultés Universitaires Notre-Dame de la Paix, Namur, Belgium.
J Phys Chem A. 2006 May 4;110(17):5952-9. doi: 10.1021/jp060541w.
We have optimized the ground-state geometry of nine series of increasingly long oligomers, using six hybrid density functionals (O3LYP, B3LYP, B97-1, B98, PBE0, and BHHLYP) combined with three different atomic basis sets. In each case, the obtained bond length alternation (BLA) is compared to the corresponding MP2 values. Three phenomenological categories have been set up. In the first, the BLA exponentially decreases, in which case all the tested functionals give results in very good agreement with MP2. In the second category fall the symmetric oligomers that, due to the Peierls theorem, show large BLA. For these chains, BHHLYP tends to give too large and quickly converging BLA wrt chain length, while O3LYP often leads to the opposite misjudgments, and the remaining hybrids provide valuable results. In the third category, one finds asymmetric compounds presenting significantly unequal bond lengths, for which the divergence between DFT and wave function approaches can be dramatic. Indeed, all hybrids yield too small BLA values, especially for long chain lengths. We also study the effect of chain conformation on the BLA.
我们使用六种杂化密度泛函（O3LYP、B3LYP、B97 - 1、B98、PBE0和BHHLYP）与三种不同的原子基组相结合，优化了九个系列长度不断增加的低聚物的基态几何结构。在每种情况下，将得到的键长交替（BLA）与相应的MP2值进行比较。已建立了三个现象学类别。在第一类中，BLA呈指数下降，在这种情况下，所有测试的泛函给出的结果与MP2非常吻合。第二类包括对称低聚物，由于佩尔斯定理，它们显示出较大的BLA。对于这些链，BHHLYP倾向于给出相对于链长度过大且迅速收敛的BLA，而O3LYP常常导致相反的错误判断，其余的杂化泛函提供了有价值的结果。在第三类中，发现不对称化合物呈现出明显不等的键长，对于这类化合物，密度泛函理论（DFT）方法和波函数方法之间的差异可能很大。实际上，所有杂化泛函都给出过小的BLA值，尤其是对于长链长度的情况。我们还研究了链构象对BLA的影响。
