An electrical circuit model of the alpha-beta merging seen in dielectric relaxation of ultraviscous liquids

作者：Saglanmak Neslihan^*; Nielsen Albena I; Olsen Niels Boye; Dyre Jeppe C; Niss Kristine

来源：Journal of Chemical Physics, 2010, 132(2): 024503.

DOI：10.1063/1.3270164

• cooling
• dielectric relaxation
• liquids

We present a new model for dielectric data in the alpha-beta merging region. The model is constructed using electrical circuit analogies. It leads to an interpretation of the merging region as one where the total relaxation upon cooling separates in two relaxation processes, consistent with a view where the relaxing entities involved are the same for the two processes. We use this alpha-beta model to fit dielectric data in the merging region of two different molecular liquids. These fits are performed under the assumption that the intrinsic high-frequency behavior of the alpha relaxation is a -1/2 power law and that both the alpha and the beta process separately obey time temperature superposition. We get good quality fits in the entire frequency and temperature range studied. This supports the view that alpha relaxation high-frequency slopes that are found to be numerically smaller than 1/2 can be attributed to the influence of the beta relaxation.

• 出版日期2010-1-14