MRC, Université Libre de Bruxelles, CP165/62, Av. F.D. Roosevelt, 50, B-1050 Bruxelles, Belgium.
J Chem Phys. 2011 Jan 28;134(4):044524. doi: 10.1063/1.3546036.
We report on the development of the optical digital interferometry (ODI) technique for measuring diffusion and Soret coefficients. The unique feature of this method is that it traces the transient path of the system in the entire two-dimensional cross section of a cell. In this way, it is applicable not only for measurements of Soret coefficients, but also for studying diffusive transport mechanism and convection. Presently, this method is not widely used and, in our view, not because of fundamental limitations but rather due to a lack of properly developed postexperimental procedures of the raw data analysis. Thus, in this paper our attention is focused on the successive analysis of different steps: the fringe analysis, the choice of reference images, the thermal design of the cell, and multiparameter fitting procedure. Using the ODI technique, we have measured the diffusion and the Soret coefficients for three binary mixtures composed of dodecane (C(12)H(26)), isobutylbenzene, and 1,2,3,4-tetrahydronaphtalene at a mean temperature of 25(∘)C and 50 wt. % in each component. These measurements were compared with their benchmark values and show an agreement within less than 3%.
我们报告了用于测量扩散系数和索雷特系数的光学数字干涉（ODI）技术的发展。该方法的独特之处在于它可以跟踪系统在整个细胞二维横截面中的瞬态路径。这样，它不仅适用于索雷特系数的测量，也适用于研究扩散传输机制和对流。目前，这种方法并没有得到广泛应用，我们认为，这不是由于基本限制，而是由于缺乏适当开发的原始数据分析后处理程序。因此，在本文中，我们将注意力集中在连续分析不同步骤上：条纹分析、参考图像的选择、细胞的热设计以及多参数拟合程序。使用 ODI 技术，我们测量了三种由十二烷（C(12)H(26)）、异丁基苯和 1,2,3,4-四氢化萘组成的二元混合物在 25(∘)C 和 50wt.%每种成分下的扩散系数和索雷特系数。这些测量值与基准值进行了比较，结果表明误差小于 3%。
