Kahle S, Gapinski J, Hinze G, Patkowski A, Meier G
Institut fuer Festkörperforschung, Forschungszentrum Jülich, Postfach 1913, 52425 Jülich, Germany.
J Chem Phys. 2005 Feb 15;122(7):074506. doi: 10.1063/1.1846653.
Depolarized dynamic light scattering (DLS), dielectric relaxation (DS), and deuterium NMR studies of fragile van der Waals glass forming liquids phenylphthalein-dimethylether (PDE) and cresolphthalein-dimethylether (KDE) are presented. In PDE a new dielectric loss process was found, which can be attributed to the 180 degrees flip of the phenyl rings. The previous finding that the distribution of the structural relaxation times measured for PDE and KDE by DS is substantially narrower than that measured by DLS is explained by partial decoupling of the dynamics of the dipole moment from the structural relaxation of the sample. The dynamics of PDE and KDE is compared with the previous studies of two other structurally similar liquids: 1,1'-di(4-methoxy-5-methylphenyl)cyclohexane (BMMPC) and 1,1'-bis(p-methoxyphenyl)cyclohexane (BMPC) in order to relate dynamical features with the chemical structure of the material. The evidence for the intramolecular character of the secondary relaxations observed in BMPC and PDE is presented.
本文介绍了对易碎的范德华玻璃形成液体邻苯二甲酸苯甲酯二甲醚（PDE）和甲酚酞二甲醚（KDE）进行的去极化动态光散射（DLS）、介电弛豫（DS）和氘核磁共振研究。在PDE中发现了一个新的介电损耗过程，这可归因于苯环的180度翻转。先前的发现，即通过DS测量的PDE和KDE的结构弛豫时间分布比通过DLS测量的窄得多，是由偶极矩动力学与样品结构弛豫的部分解耦来解释的。将PDE和KDE的动力学与另外两种结构相似的液体：1,1'-二（4-甲氧基-5-甲基苯基）环己烷（BMMPC）和1,1'-双（对甲氧基苯基）环己烷（BMPC）的先前研究进行比较，以便将动力学特征与材料的化学结构联系起来。文中给出了在BMPC和PDE中观察到的二级弛豫的分子内特征的证据。
