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

在这个由化学部门实验物理化学项目支持的RUI项目中，Spiegel将利用振幅校准强迫瑞利散射（AC-FRS）来研究聚合物溶液中的小分子扩散。该方法将用于测量光产物和基态探针扩散，以开发通过聚合物溶液和固体的分子扩散的原位光学控制，包括非线性光学聚合物波导。初步实验将检查光诱导偶氮苯和螺吡喃在极性垂坠基团聚合物中的扩散系数的变化。不带电分子通过复杂溶液（如聚合物）在微观长度上的扩散是化学、化学工程和生物学中经常发生的过程。尽管如此，仍有许多基本的物理问题尚未解决。这个项目将研究一些相互作用，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率非常重要。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.