Time-Resolved, Electric-Field-Induced Vibrational Spectroscopy for Molecular Conformation Studies

在化学系化学测量和成像以及化学结构、动力学和机制项目的支持下，加州大学圣地亚哥分校的熊教授和帕萨尼教授正在开发新的方法来研究分子及其在界面上的行为。这项研究对于优化许多化学系统和装置的性能是必不可少的。该团队正在使用实验和理论相结合的方法，为一些重要的社会需求找到技术解决方案，从可再生能源到下一代柔性电子产品和显示器。这一合作研究项目为参与的学生提供了激光光谱学和计算化学的独特体验，从而促进了加州大学圣地亚哥分校的跨学科研究。该项目还为本科生提供了机会，通过暑期研究项目和其他现有的以加州大学圣地亚哥分校为基础的扩展项目，获得尖端技术的实践研究经验。提出的时间分辨电场诱导外差和频率谱使界面电荷转移的研究成为可能，并提供了对复杂界面上分子物理和超快电荷转移动力学之间隐藏关系的深入理解。多维SFG是最近发展起来的一种光谱技术，它可以分辨非均相界面上各种构象的精细光谱特征。结合计算机模拟，揭示了分子构象和光谱关系。时间分辨的电场诱导效应通过调制SFG信号实现了界面上的超快电荷转移。通过将时间分辨电场诱导效应与多维SFG光谱相结合，发现了有利于复杂界面电荷动力学的分子构象。这一新方法被用来研究有机半导体和金属或无机半导体之间的界面电荷转移。这一奖项反映了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 support from the Chemical Measurement and Imaging and Chemical Structure, Dynamics and Mechanisms programs in the Division of Chemistry, Professors Xiong and Paesani at University of California, San Diego, are developing new methods for studying molecules and their behaviors at interfaces. The study is essential for optimizing performance of many chemical systems and devices. The team is using a combined experimental and theoretical approach to find a technical solution for some important societal needs, ranging from renewable energy to next generation flexible electronics and displays. This collaborative research project provides participating students with unique experiences at the interface of laser spectroscopy and computational chemistry, and thus promotes interdisciplinary research at University of California, San Diego. This project also provides opportunities for undergraduate students to gain hands-on research experience with cutting-edge technology through a summer research program and through other existing UCSD-based outreach programs. The proposed time-resolved electric-field-induced heterodyne sum frequency spectroscopy enables studies of interfacial charge transfer and delivers an in-depth understanding of hidden relationships between molecular physics and ultrafast charge transfer dynamics at complex interfaces. The multidimensional SFG is a recently developed spectroscopic technique that can resolve fine spectral signatures of various conformations on heterogeneous interfaces. Together with computer simulation, molecular conformation and spectral relationships are revealed. The time-resolved electric-field-induced effect enables following ultrafast charge transfer at interfaces through the modulation of SFG signals. By integrating time-resolved electric-filed-induce effect with the multidimensional SFG spectroscopy, molecular conformations that favor charge dynamics at complex interfaces are discovered. This new approach is used to study interfacial charge transfer between organic semiconductors and metal or inorganic semiconductors.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.