Molecular Radiation and Relaxation Processes

加州大学欧文分校的 Shaul Mukamel 获得理论和计算化学项目奖项的支持，继续他的研究项目，旨在开发理论和计算方法来预测分子对各种外部场（例如光、电流和其他分子）的响应。 这项理论工作提出了与多维相干超快激光光谱和量子结中分子的电流测量相关的新实验方法。 研究过程中正在开发一套用于真实空间和实时分析的工具：正在识别发色团聚集体的相干飞秒光谱中激子传输的特征；正在预测结中单电子转移事件和单分子光谱中发射的光子的统计数据，并将用于探索与驱动系统的功分布和熵产生相关的涨落定理的量子推广；正在研究处于非平衡稳态和稳态之间转变的量子系统的涨落和响应函数；量子电动力学技术被用来预测光子计数统计数据，并在时间和频率解析的非线性响应函数之间建立基本联系。这提供了输入场和信号场的微观描述，并允许 PI 和他的学生开发新的光信号近似方案。通过监测分子中电子和原子核对外部扰动（如光场、电流，甚至被探测分子对与相邻分子相互作用的响应）的响应，可以有效地探测分子中电子和原子核的动力学。 Mukamel 的工作是为实验科学家提供分析不同类型实验产生的数据所需的理论工具。 通过世界各地科学家的应用以及该小组学生接受的高度跨学科培训，这项工作正在产生更广泛的影响。 这项研究的成果已通过 Mukamel 的教科书《非线性光学光谱原理》广泛传播，他计划在下一个支持期间更新和扩展该教科书。 预计这将进一步扩大资助工作的影响。

Shaul Mukamel of the University of California Irvine is supported by an award from the Theoretical and Computational Chemistry program to continue his research program aimed at developing theoretical and computational methods for predicting the response of molecules to various external fields, such as light, electric current and other molecules. New experimental approaches related to multidimensional coherent ultrafast laser spectroscopy and to electric current measurements on molecules in quantum junctions are suggested by this theoretical work. A set of tools for their analysis in real space and real time is being developed in the course of the research: signatures of exciton transport in coherent femtosecond optical spectroscopy of chromophore aggregates are being identified; the statistics of single electron transfer events in junctions and of photons emitted in single molecule spectroscopy are being predicted and will be used to explore quantum generalizations of fluctuation theorems connected with the distribution of work and entropy production of driven systems; fluctuations and response functions of quantum systems in nonequilibrium steady states and undergoing transitions between steady states are being studied; and techniques of quantum electrodynamics are being used to predict photon counting statistics and establish fundamental connections between time and frequency resolved nonlinear response functions. This is providing a microscopic description of the incoming and signal fields and allowing the PI and his students to develop new approximation schemes for optical signals.The dynamics of electrons and nuclei in molecules can be effectively probed by monitoring their response to external perturbations such as optical fields, electrical currents and even the response of the probed molecule to interactions with neighboring molecules. Mukamel's work is providing the theoretical tools needed by experimental scientists for analyzing the data produced by different types of experiments. The work is having a broader impact through its application by scientists around the world as well as through the highly interdisciplinary training received by the students in the group. The results of this research have been widely disseminated through Mukamel's textbook, "Principles of Nonlinear Optical Spectroscopy," which he plans to update and expand in the next period of support. This is expected to further broaden the impact of the funded work.