Molecular Radiation and Relaxation Processes

加州大学欧文分校的Shaul Mukamel获得了理论与计算化学项目的奖励，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（如光、电流和其他分子）的反应。本理论工作提出了多维相干超快激光光谱和量子结中分子电流测量的新实验方法。在研究过程中，正在开发一套用于在实际空间和实时分析它们的工具：正在确定发色团聚集体的相干飞秒光学光谱中的激子输运特征；正在预测结中的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；研究了处于非平衡稳态和在稳态之间发生跃迁的量子系统的涨落和响应函数；量子电动力学技术被用于预测光子计数统计，并在时间和频率分辨非线性响应函数之间建立基本联系。这提供了入射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界扰动（如光场、电流）的响应，甚至被探测分子对与邻近分子相互作用的响应，可以有效地探测分子中的电子和原子核的动力学。Mukamel的工作为实验科学家提供了分析不同类型实验产生的数据所需的理论工具。这项工作正在产生更广泛的影响，因为它被世界各地的科学家应用，也因为该小组的学生接受了高度跨学科的培训。这项研究的结果已经通过Mukamel的教科书“非线性光谱学原理”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受资助工作的影响。

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.