Hydrogen network fluctuations and dielectric spectrometry of liquids
Hydrogen network fluctuations and dielectric spectrometry of liquids
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DOI：
10.1016/s0022-3093(02)01084-0
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发表时间：
2002-07-01
影响因子：
3.5
通讯作者：
Pottel, R
中科院分区：
文献类型：
--
作者：
Kaatze, U;Behrends, R;Pottel, R
提出了缔合液体的复介电谱，并考虑其弛豫性质进行了讨论。特别强调的是水和水溶液以及醇和醇与偶极和非极性溶剂的混合物。的关联系统的弛豫性能进行检查，在光的等待和开关模型的介电弛豫中的弛豫时间是由一个给定的整体的氢键合作伙伴内的氢网络必须等待，直到有利的条件下存在的分子永久偶极子的重新取向的期间。这些条件由另外的分子或基团提供，其首先倾向于降低重新取向的势能势垒，其次，同时提供形成新氢键的位点。一些实验结果进行了讨论的等待和开关模型，其中减少水的介电弛豫时间tinder静水压力，负离子和疏水水合的影响，以及水的影响，一方面，和正构烷烃，另一方面，对醇的松弛作用。(C)2002 Elsevier Science B.V.保留所有权利。
Complex dielectric spectra of associating liquids are presented and are discussed considering their relaxation properties. Particular emphasis is given to water and aqueous solutions and to alcohols and mixtures of alcohols with dipolar and non-polar solvents. The relaxation properties of the associating systems are examined in the light of a wait-and-switch model of dielectric relaxation in which the relaxation time is governed by the period for which a given ensemble of hydrogen bond partners within the hydrogen network has to wait until favorable conditions for a reorientation of a molecular permanent dipole exist. These conditions are provided by an additional molecule or group which firstly tends to lower the potential energy barrier for reorientation and which secondly, at the same time, offers a site for the formation of a new hydrogen bond. Some experimental findings are discussed in terms of the wait-and-switch model, among them the reduced dielectric relaxation time of water tinder hydrostatic pressure, effects of negative and hydrophobic hydration of ions, and the influence that water, on the one hand, and n-alkanes, on the other hand, act on the relaxation of alcohols. (C) 2002 Elsevier Science B.V. All rights reserved.