Dipartimento di Chimica, Università di Perugia, via Elce di Sotto, I-06123 Perugia, Italy.
J Chem Phys. 2010 Jun 7;132(21):214508. doi: 10.1063/1.3430555.
High resolution depolarized light scattering spectra, extended from 0.5 to 2x10(4) GHz by the combined used of a dispersive and an interferometric setup, give evidence of separated solute and solvent dynamics in diluted trehalose aqueous solutions. The slow relaxation process, located in the gigahertz frequency region, is analyzed as a function of temperature and concentration and assigned to the rotational diffusion of the sugar molecule. The results are discussed in comparison with the data obtained on glucose solutions and they are used to clarify the molecular origin of some among the several relaxation processes reported in literature for oligosaccharides solutions. The concentration dependence of relaxation time and of shear viscosity are also discussed, suggesting that the main effect of carbohydrate molecules on the structural relaxation of diluted aqueous solutions is the perturbation induced on the dynamics of the first hydration shell of each solute molecule.
高分辨率去偏振光散射光谱，通过组合使用分光和干涉装置，扩展到 0.5 到 2x10(4) GHz，在稀释的海藻糖水溶液中证明了溶质和溶剂的分离动力学。位于千兆赫频率区域的缓慢弛豫过程，作为温度和浓度的函数进行分析，并归因于糖分子的旋转扩散。结果与葡萄糖溶液的实验数据进行了比较，并用于澄清文献中报道的寡糖溶液的几种弛豫过程中的一些的分子起源。还讨论了弛豫时间和剪切粘度的浓度依赖性，表明碳水化合物分子对稀释水溶液结构弛豫的主要影响是对每个溶质分子的第一水合壳的动力学的扰动。
