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首页> 外文期刊>The journal of physical chemistry, A. Molecules, spectroscopy, kinetics, environment, & general theory >An evaluation of scaling factors for multiparameter scaling procedures based on DFT force fields
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An evaluation of scaling factors for multiparameter scaling procedures based on DFT force fields

机译：基于DFT力场的多参数缩放过程的缩放因子评估

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摘要

An extended database of scaling factors for calculating fundamental frequencies within multiparameter scaled quantum mechanical (SQM) force field, and effective scaling frequency factor (ESFF) methods, based on various DFT force fields is reported. Twenty-six density functionals have been examined in conjunction with various Poples and Dunnings basis sets of VDZ and VTZ quality. The calculations were based on a standard training set of 30 molecules proposed by Baker et al., for which 660 vibrational modes were assigned. Six functionals turned out to be particularly well-suited to the calculations oriented toward determination of scaled frequencies. They are B3LYP, B3PW91, B97, B97-1, B97-2, and O3LYP; they are all capable of providing reasonable scaled frequencies even for the small, 6-31G* basis set (rms <15 cm ~(-1)). Correlations between the quality of the scaled frequencies and the basis set quality as well as the accuracy of the predicted molecular geometry were investigated. The 6-311+G* basis set turned out to be preferable. In addition, correlation between the rms values in the scaled frequencies and the errors in the predicted geometric parameters was found. Both 11-and 9-parameter scaling frames are compared. It is shown that 9-parameter scaling is preferable in the middle range of the vibrational spectrum (500-2500 cm ~(-1)), provided it was based on high-quality force fields. Finally, statistical uncertainties of the calculated scaling factors are reported.
机译：报告了扩展的比例因子数据库，用于计算多参数比例量子力学（SQM）力场内的基本频率，以及基于各种DFT力场的有效比例频率因子（ESFF）方法。已与VDZ和VTZ质量的各种Poples和Dunnings基础集一起检查了26种密度泛函。该计算基于贝克等人提出的30个分子的标准训练集，并为其分配了660种振动模式。事实证明，六个功能特别适合于确定比例频率的计算。它们是B3LYP，B3PW91，B97，B97-1，B97-2和O3LYP;即使对于较小的6-31G *基组（均方根<15 cm〜（-1）），它们都能够提供合理的定标频率。研究了定标频率的质量与基集质量以及预测的分子几何形状的准确性之间的相关性。事实证明，6-311 + G *基数更好。另外，找到了标度频率中的均方根值与预测几何参数误差之间的相关性。比较11参数和9参数缩放帧。结果表明，如果基于高质量的力场，则在振动谱的中间范围（500-2500 cm〜（-1））中，最好使用9参数缩放。最后，报告了计算出的比例因子的统计不确定性。

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