Schröder Christian, Sega Marcello, Schmollngruber Michael, Gailberger Elias, Braun Daniel, Steinhauser Othmar
Department of Computational Biological Chemistry, University of Vienna, Währingerstrasse 17, A- 1090 Vienna, Austria.
J Chem Phys. 2014 May 28;140(20):204505. doi: 10.1063/1.4878116.
Dielectric spectroscopy is a measure of the collective Coulomb interaction in liquid systems. Adding ionic liquids to an aqueous solution results in a decrease of the static value of the generalized dielectric constant which cannot be attributed to kinetic depolarization models characterized by the static conductivity and rotational relaxation constant. However, a dipolar Poisson-Boltzmann model computing the water depolarization in the proximity of ions is not only successful for simple electrolytes but also in case of molecular ionic liquids. Moreover, our simple geometric hydration model is also capable to explain the dielectric depolarization. Both models compute the dielectric constant of water and obtain the overall dielectric constant by averaging the values of its components, water and the ionic liquid, weighted by their volume occupancies. In this sense, aqueous ionic liquid mixtures seem to behave like polar mixtures.
介电谱是对液体系统中集体库仑相互作用的一种度量。向水溶液中添加离子液体导致广义介电常数的静态值降低，这不能归因于以静态电导率和旋转弛豫常数为特征的动力学去极化模型。然而，计算离子附近水去极化的偶极泊松 - 玻尔兹曼模型不仅对简单电解质有效，对分子离子液体也有效。此外，我们简单的几何水合模型也能够解释介电去极化。这两种模型都计算水的介电常数，并通过对其组分（水和离子液体）的值进行平均来获得总体介电常数，权重为它们的体积占有率。从这个意义上说，水性离子液体混合物的行为似乎类似于极性混合物。
