Fundamental New Experiments on Molecular Diffusion in Complex Solutions: Amplitude-Calibrated Forced Rayleigh Scattering

在这个由化学部实验物理化学计划支持的RUI项目中，Spiegel将利用幅度校准的强迫瑞利散射(AC-FRS)来研究小分子在聚合物溶液中的扩散。这种方法将被用来测量光生产物和基态探测器的扩散，以便开发对通过聚合物溶液和固体，包括非线性光学聚合物波导的分子扩散的原位光学控制。最初的实验将检验偶氮苯和螺吡喃在极性侧基聚合物中的光诱导扩散系数的变化。在化学、化学工程和生物学中，不带电荷的分子通过聚合物等复杂溶液在微观长度上扩散是一个常见的过程。尽管如此，仍有许多基本的物理问题尚未得到解决。这个项目将考察一些相互作用，这些相互作用对于理解如何利用光来控制中性粒子在聚合物固体和溶液中的扩散速度是重要的。这种现象对高速非线性光纤技术具有重要意义。

In this RUI project supported by the Experimental Physical Chemistry Program of the Chemistry Division, Spiegel will utilize amplitude-calibrated forced Rayleigh scattering (AC-FRS) to investigate small-molecule diffusion in polymer solutions. This method will be used to measure photoproduct and ground-state probe diffusion in order to develop in-situ optical control of molecular diffusion through polymer solutions and solids, including nonlinear-optical polymer waveguides. Initial experiments will examine photoinduced changes in the diffusion coefficients of azobenzenes and spiropyrans within polar-pendant group polymers. The diffusion of uncharged molecules across microscopic lengths through complex solutions such as polymers is a commonly occurring process in chemistry, chemical engineering, and biology. Nonetheless, there are many fundamental physical issues which have not been addressed. This project will look at some of the interactions which are important in understanding how to use light to control the rates of diffusion of neutral particles in polymer solids and solutions. This type of phenomenon has implications for high-speed nonlinear fiber optics technology.