Solvation and Reaction Dynamics in Heterogeneous Environments

科罗拉多州立大学的Branka Ladanyi得到了理论与计算化学项目的资助，研究了反胶束极性溶剂池和极性溶剂团簇中的溶剂化和反应动力学。在这两种情况下，研究将集中于极性分子的数量在一个簇或一个反胶团如何影响溶剂化和反应性。主要目的是解释观察到的与本体溶剂化的巨大差异。在反胶束的情况下，Ladanyi将研究水池的大小和其他因素，如反离子身份和反胶束内溶质位置，如何影响溶剂化动力学和热力学。这将通过分子动力学模拟和分析轨迹数据来确定重要的溶剂化机制及其对溶剂环境异质性的依赖。这些研究将使用一系列模型，从仅内部区域的原子表示开始，到表面活性剂尾部和非极性溶剂的完全原子表示。在极性团簇的溶剂化和反应性方面，Ladanyi将把她之前关于溶剂化碘化钠的溶剂化和光解动力学的工作扩展到其他碱卤化物，主要是氯化钠，以及其他极性溶剂，特别是乙腈和氨。这项工作的目标是确定，在分子水平上，与不同数量的极性溶剂分子的相互作用如何影响溶质的电子状态，以及这对平衡溶剂化和光化学的影响。蒙特卡罗和非绝热分子动力学模拟方法将在这项工作中使用。大部分工作将用于解释南希·莱文格在反胶束上获得的实验结果。由于大多数化学反应都是在溶剂存在的情况下发生的，因此了解和预测溶剂对反应的影响一直是化学研究的长期目标。近年来，在分子水平上对溶剂对化学反应性影响的认识取得了很大进展。理论和计算方法使研究日益复杂的系统和现象成为可能。理论模型正在扩展到发生在生物和技术重要过程中的异质化学环境。Ladanyi将在具有重要技术意义的反胶束中进行极性溶剂化模拟，并作为理解生物系统中溶剂化的模型系统。

Branka Ladanyi of Colorado State University is supported by a grant from the Theoretical and Computational Chemistry Program to investigate solvation and reaction dynamics in the polar solvent pool of reverse micelles and in polar solvent clusters. In both cases research will focus on how the number of polar molecules within a cluster or a reverse micelle affects solvation and reactivity. The primary goal is to explain observations of large differences from bulk solvation. In the case of reverse micelles, Ladanyi will investigate how the size of the water pool and other factors, such as counterion identity and solute location within the reverse micelle, affect solvation dynamics and thermodynamics. This will be done using molecular dynamics simulations and analyzing the trajectory data to identify the important solvation mechanisms and their dependence on the heterogeneity of the solvent environment. A hierarchy of models, starting from an atomistic representation of only the interior region and progressing to a fully atomistic representation of the surfactant tails and the nonpolar solvent, will be used in these studies. In the case of solvation and reactivity in polar clusters, Ladanyi will extend her previous work on solvation and photodissociation dynamics of solvated sodium iodide to other alkali halides, primarily to sodium chloride, and to other polar solvents, in particular acetonitrile and ammonia. The goal of this work is to determine, at the molecular level, how interactions with varying numbers of polar solvent molecules affect the electronic states of the solute and the consequences of this for equilibrium solvation and photochemistry. Monte Carlo and nonadiabatic molecular dynamics simulation methods will be used in this work. Much of the work will be used to interpret the experimental results obtained by Nancy Levinger on reverse micelles. Since most chemical reactions happen in the presence of solvents, understanding and predicting the effects of solvents on reactions has been a longstanding goal of chemical research. In recent years there has been a great deal of progress towards the molecular level understanding of solvent effects on chemical reactivity. Theoretical and computational methods are now making it possible to study increasingly complex systems and phenomena. Theoretical models are extending to heterogeneous chemical environments that occur in biological and technologically important processes. Ladanyi will perform simulations on polar solvation in reverse micelles that have significant technological importance, and that serve as model systems for understanding solvation in biological systems.