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Multidimensional Femtosecond Studies of Chemical Reaction Dynamics

化学反应动力学的多维飞秒研究

基本信息

批准号：
1800523
负责人：
David Jonas
金额：
$ 50.23万
依托单位：
University of Colorado at Boulder
依托单位国家：
美国
项目类别：
Continuing Grant
财政年份：
2018
资助国家：
美国
起止时间：
2018-09-01 至 2022-08-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1800523&HistoricalAwards=false
关键词：
Multidimensional Femtosecond Studies Chemical Reaction

项目摘要

This project is funded by the Chemical Structure, Dynamics and Mechanism (CSDM-A) program of the Chemistry Division. Professor David Jonas of the University of Colorado at Boulder is developing femtosecond laser techniques to study the motion of electrons in molecules. A femtosecond is a millionth of a billionth of a second. Inside molecules, atoms and slow electrons move on the femtosecond timescale. The goal of the project is to measure how atomic and electronic motions are linked when the forces driving their motion are weak. Such weak forces can arise from energies on the order of the thermal energy. This project explores the smallest energy required to drive motion of electrons. Similar electronic motions are involved in lighting, displays, and photosynthesis. Three dimensional spectra correlate electronic and atomic motion. High symmetry molecules simplify the study of electronic and atomic motions.In 3D Fourier transform spectroscopy, four-wave mixing is used to record transient signals as a function of three time delays between pulses. Triple Fourier transformation with respect to the three time delays generates a spectrum that is a function of three frequency axes. Unlike most 2D spectra, the pulse spectra and pulse propagation effects can be divided out in 3D. This reveals the underlying 3D nonlinear response, which should be independent of experimental conditions. The signal from cross-phase modulation in transparent solvents produces compact time-domain transients for initial experimental recovery of the underlying 3D response. 2D and 3D electronic spectroscopy of high symmetry molecules with pseudo Jahn-Teller effects can reveal the mechanism of their femtosecond electronic population transfer through comparison to quantum mechanical calculations. The calculations fully incorporate non-adiabatic interactions between motion of electrons and the vibrational motion of atoms. The broader impacts of this project include training of students in modern experimental and computational techniques plus potential societal benefits from a better understanding of the minimum energy required to drive electronic motion.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.

该项目由化学部的化学结构，动力学和机制（CSDM-A）计划资助。位于博尔德的科罗拉多大学的大卫乔纳斯教授正在开发飞秒激光技术来研究分子中电子的运动。飞秒是十亿分之一秒的百万分之一。在分子内部，原子和慢电子在飞秒时间尺度上运动。该项目的目标是测量当驱动它们运动的力很弱时，原子和电子运动是如何联系在一起的。这种弱力可以由热能量级的能量产生。该项目探索驱动电子运动所需的最小能量。类似的电子运动涉及照明、显示和光合作用。三维光谱将电子和原子的运动联系起来。高对称性分子简化了电子和原子运动的研究。在3D傅里叶变换光谱学中，四波混频用于记录作为脉冲之间三个时间延迟的函数的瞬态信号。相对于三个时间延迟的三重傅立叶变换生成作为三个频率轴的函数的频谱。与大多数2D光谱不同，脉冲光谱和脉冲传播效应可以在3D中划分。这揭示了潜在的3D非线性响应，这应该是独立的实验条件。来自透明溶剂中的交叉相位调制的信号产生紧凑的时域瞬态，用于基础3D响应的初始实验恢复。具有赝Jahn-Teller效应的高对称性分子的二维和三维电子光谱可以通过与量子力学计算的比较揭示其飞秒电子布居转移的机制。计算中充分考虑了电子运动和原子振动之间的非绝热相互作用。该项目的广泛影响包括对学生进行现代实验和计算技术的培训，以及更好地理解驱动电子运动所需的最低能量所带来的潜在社会效益。该奖项反映了NSF的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。