Cammi Roberto
Department of Chemistry, Life Science and Environmental Sustainability, University of Parma, I-43100, Parma, Italy.
J Comput Chem. 2019 Oct 5;40(26):2309-2317. doi: 10.1002/jcc.26009. Epub 2019 Jun 27.
The methods for the experimental determination of electric dipole moment of molecules in solution from measurements of dielectric permittivity and refractive index are traditionally based on the classical Onsager model. In this model the molecular solute is approximated as a simple polarizable point dipole inside a spherical or ellipsoidal cavity of a dielectric medium representing the solvent. However, the inadequacies of the model resulting from the assumption of a simple shape of the cavity, for the evaluation of the cavity field effect, and from the uncertainty of the polarizability of the molecular solute influences the results and hampers the comparison with the electric dipole moments computed from quantum chemical solvation models. In this article we propose a new method for the experimental determination of the electric dipole moment in solution in which information from the Polarizable Continuum Model calculations are used in place of the Onsager model. The new method overcomes the limitations of this latter model regarding both the cavity field effect and the polarizability of the molecular solutes, and thus allows a coherent comparison between experimental and computed dipole moments of solvated molecules. © 2019 Wiley Periodicals, Inc.
传统上，根据介电常数和折射率的测量结果来实验测定溶液中分子电偶极矩的方法是基于经典的昂萨格模型。在该模型中，分子溶质近似为处于代表溶剂的介电介质的球形或椭球形空腔内的一个简单的可极化点偶极子。然而，由于在评估空腔场效应时假设空腔形状简单，以及分子溶质极化率的不确定性，该模型存在不足之处，这影响了结果，并妨碍了与从量子化学溶剂化模型计算出的电偶极矩进行比较。在本文中，我们提出了一种用于实验测定溶液中电偶极矩的新方法，其中使用来自可极化连续介质模型计算的信息来替代昂萨格模型。新方法克服了后一种模型在空腔场效应和分子溶质极化率方面的局限性，从而使得溶剂化分子的实验偶极矩与计算偶极矩之间能够进行连贯的比较。© 2019威利期刊公司。
