DMSO-乙醇混合溶液相对介电常数特异性的理论与实验研究

Dielectric properties of DMSO–ethanol mixtures: density functional theory and experiment

摘要:

在20℃下分别测量了二甲基亚砜（DMSO）、乙醇及其混合溶液的相对介电常数，发现某些浓度的混合溶液的相对介电常数虚部大于其任一组分的相对介电常数虚部的特异现象。为解释该特异现象，本文基于密度泛函理论对 (DMSO)m(C2H5OH)n (m+n≤4)团簇进行了系统研究，并给出了相应分子团簇的团簇半径。通过分析分子团簇的团簇半径，发现计算结果可以很好的解释DMSO-乙醇混合溶液相对介电常数虚部出现的特异行为。

Abstract:

The relative permittivity of dimethyl sulfoxide (DMSO) solutions, ethanol (C2H5OH) solutions and their mixtures have been measured at 20 ℃, respectively. Surprisingly, at certain concentration, it appears an exceptional phenomenon that the imaginary part of mixtures relative permittivity is larger than that of their pure components. To explain the exceptional phenomenon on the mixtures relative permittivity, a systematical investigation about the molecular clusters ((DMSO)m(C2H5OH)n) as well as their cluster radii have been given using DFT calculations. Comparing the cluster radii of the binary clusters ((DMSO)m(C5H5N)n) with that of the pure clusters ((DMSO)m and (C2H5OH)n), the results have given an reasonable explanation of the exceptional phenomenon on the imaginary part of the mixtures relative permittivity.