Harmonic and Anharmonic Vibrational Frequency Calculations with the Double-Hybrid B2PLYP Method: Analytic Second Derivatives and Benchmark Studies
Harmonic and Anharmonic Vibrational Frequency Calculations with the Double-Hybrid B2PLYP Method: Analytic Second Derivatives and Benchmark Studies
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DOI：
10.1021/ct100212p
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发表时间：
2010-07-01
影响因子：
5.5
通讯作者：
Barone, Vincenzo
中科院分区：
文献类型：
--
作者：
Biczysko, Malgorzata;Panek, Pawel;Barone, Vincenzo
这项工作的目的是提供可靠的基准数据与B2 PLYP双杂化密度泛函方法计算的谐波和非谐波振动频率的准确性。交换相关的贡献所需的B2 PLYP分析的二阶导数在这里，它允许谐波频率以及立方和半对角四次力场的有效计算。后者，反过来，是必要的计算与微扰方法（VPT 2）的非谐振动频率。结合双到四重zeta质量的基础集计算的谐波振动频率的质量已经检查了F38基准集的参考数据。然后，对于另一组小的封闭和开放壳层系统，在B2 PLYP/N 07 D和B2 PLYP/aug-cc-pVTZ水平上计算的谐波频率和非谐波贡献与CCSD（T）对应物进行了比较。此外，对于选定的中等大小的分子（呋喃，吡咯，噻吩，尿嘧啶，苯甲醚，苯酚，和吡啶），非谐波频率进行了比较，以及建立的实验结果。这样的基准研究表明，B2 PLYP/N 07 D模型提供了良好的质量谐波频率和正确的描述非谐波的贡献，后者是类似的精度，他们的B3 LYP/N 07 D对应，但在显着更大的计算成本获得。此外，通过采用混合模型可以获得更高的精度，其中B2 PLYP/N 07 D谐波贡献与用更精确的量子力学（QM）方法计算的谐波频率相结合，或者通过具有更大基组的B2 PLYP计算。这项工作也证实，大多数最近开发的密度泛函显着不适合振动计算，而B2 PLYP方法可以推荐用于光谱研究，其中需要良好的振动性质的准确性。
This work aims to provide reliable benchmark data on the accuracy of harmonic and anharmonic vibrational frequencies computed with the B2PLYP double-hybrid density functional method. The exchange-correlation contributions required for the B2PLYP analytical second derivatives are presented here, which allow for the effective calculation of harmonic frequency as well as cubic and semidiagonal quartic force fields. The latter, in turn, are necessary to compute the anharmonic vibrational frequencies with the perturbative approach (VPT2). The quality of harmonic vibrational frequencies computed in conjunction with basis sets of double- to quadruple-zeta quality has been checked against reference data from the F38 benchmark set. Then, for an additional set of small closed- and open-shell systems, both harmonic frequencies and anharmonic contributions computed at the B2PLYP/N07D and the B2PLYP/aug-cc-pVTZ levels have been compared to their CCSD(T) counterparts. Moreover, for selected medium-size molecules (furan, pyrrole, thiophene, uracil, anisole, phenol, and pyridine), anharmonic frequencies have been compared to well established experimental results. Such benchmark studies have shown that the B2PLYP/N07D model provides good quality harmonic frequencies and describes correctly anharmonic contributions, the latter being of similar accuracy to their B3LYP/N07D counterparts, but obtained at significantly larger computational cost. Additionally, increased accuracy can be obtained by adopting hybrid models where the B2PLYP/N07D an harmonic contributions are combined with harmonic frequencies computed with more accurate quantum mechanical (QM) approaches or by B2PLYP with larger basis sets. This work confirmed also that most of the recently developed density functionals are significantly less suited for vibrational computations, while the B2PLYP method can be recommended for spectroscopic studies where a good accuracy of vibrational properties is required.