Collaborative Research: Soft Interfaces and Charge Separation Stabilization

在化学部化学结构动力学和机理(CSDM-A)计划的资助下，俄亥俄州立大学的Heather C.Allen和加州大学伯克利分校的David T.Limmer正在使用最先进的实验和计算工具来了解软界面上的化学。软界面是指包含两个相的界面，如液态水及其蒸汽，具有分子宽度的过渡区。这些界面的性质可能很难预测，特别是它们如何影响化学反应的结果。PI将通过检测在不同溶剂表面具有明显不同电子结构的相关气相分子来克服这些技术挑战。这一系统的方法预计将提供对软表面上发生化学反应的一般情况的洞察，对大气和工业化学具有潜在的影响。该项目正在支持俄亥俄州立大学的一名研究生和博士后助理以及加州大学伯克利分校的一名研究生的培训。除了正式的研究、培训和教育外，该项目还将支持开发可用于普通化学课程的界面动力学分子动力学(MD)模拟视频，以加强平衡和界面化学概念。该项目侧重于调节溶液的介电常数和粘度，并将利用气相分子N2O5和N2O4作为界面探针，以实现电荷稳定。这些分子在界面上具有显著不同的反应活性，因为N2O5引起了显著的电荷分离，而N2O4则没有。具有不同极性、链长和结构的溶剂将被研究来调节这些内在差异。实验观察将借助使用人工神经网络势的分子动力学模拟来解释。这项研究的更广泛的影响包括增加对界面反应性的了解的社会效益，特别关注大气气溶胶的界面调节。此外，这种高度协作和结合的理论和实验研究将为研究生和博士后研究人员的培训提供良好的机会。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

With funding from the Chemical Structure Dynamics and Mechanisms-A (CSDM-A) Program of the Chemistry Division, Heather C. Allen at Ohio State University and David T. Limmer at University of California-Berkeley are using state-of-the-art experimental and computational tools to understand chemistry at soft interfaces. Soft interfaces are those involving two phases, like liquid water and its vapor, with a transition zone of molecular width. Properties of these interfaces can be difficult to predict, especially how they affect the outcomes of chemical reactions. The PIs will overcome these technical challenges by examining related gas phase molecules that have distinctly different electronic structures at the surface of different solvents. This systematic approach is expected to provide insight into how chemical reactions occur at soft surfaces generally, with potential implications to atmospheric and industrial chemistry. This project is supporting the training of a graduate student and a post-doctoral associate at Ohio State, and a graduate student at UC-Berkeley. In addition to formal research training and education, the project will support the development of videos on molecular dynamics (MD) simulation of interfacial dynamics that can be used in General Chemistry courses to reinforce equilibrium and interfacial chemistry concepts.The project focuses on tuning the dielectric constant and viscosity of solutions and will utilize gas phase molecules, N2O5 and N2O4, as interfacial probes of their resultant charge stabilization. These molecules possess significantly different reactivities at interfaces, as N2O5 elicits a significant level of charge separation whereas N2O4 does not. Solvents with different polarities, chain lengths and structures will be studied to modulate these intrinsic differences. Experimental observations will be interpreted with the help of molecular dynamics simulations employing artificial neural network potentials. The broader impacts of this research include societal benefits from an increased understanding interfacial reactivity, with particular attention to the interfacial accommodation of atmospheric aerosols. In addition, this highly collaborative and combined theoretical and experimental inquiry will provide good opportunities for the training of graduate students and postdoctoral research associates.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.