The influence of the composition of the functional used for density functional theory computations on one structural parameter (a dihedral angle) and a spectroscopic parameter (absorption wavelength) is assessed in this study on the basis of two molecules (flavonols). In this kind of molecules, these two parameters should be correlated according to the nature of the electronic transition involved. However, it is shown herein that by varying the proportion of true exchange and correlation while building a functional, it is possible to obtain independently a large range of values for these parameters without any relation with the underlying real values. Therefore, it is concluded that the choice of a functional after a benchmark, especially using user‐defined functionals, should be carried out with great care to avoid such effects.

中文翻译：

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密度泛函理论中交换和相关参数的正交效应计算几何和光谱量

本研究基于两个分子（黄酮醇）评估了用于密度泛函理论计算的泛函组成对一个结构参数（二面角）和光谱参数（吸收波长）的影响。在这种分子中，这两个参数应该根据所涉及的电子跃迁的性质相关联。然而，本文示出了通过在构建泛函时改变真实交换和相关性的比例，可以独立地获得这些参数的大范围的值，而与底层实际值没有任何关系。因此，得出的结论是，在基准测试之后选择函数，尤其是使用用户定义的函数，应该非常小心，以避免这种影响。