OP-Molecular Radiative and Relaxation Processes

加州大学欧文分校的Shaul Mukamel得到了化学系化学理论、模型和计算方法项目的奖励。穆卡迈尔和他的同事设计了尖端的光谱学实验，并开发了解释结果的模型和方法。了解和控制分子中电子和原子核的运动可以决定化学反应和能量转移过程的速率和结果。其中包括在自然光合作用和人工采光装置中将太阳能转化为电能。这个项目开发了通过测量复杂分子对超快激光脉冲序列的响应来研究这些基本事件的方法。这种实验是由新开发的激光光源实现的。为了解释和分析这些实验并提取潜在的分子信息，开发了模型和实用的计算工具。Mukamel教授和他的研究小组与世界各地领先的实验研究小组密切合作，设计了涉及仔细定时的脉冲序列的新实验技术，并将其广泛应用于分子和分子聚集体以及凝聚相。发展了旨在直接检测电子和振动相干以及非绝热动力学的光谱技术，其中Born Oppenheimer近似被打破。设计了可以直接探测分子通过锥形交叉口的宽带共振和非共振拉曼技术，并开发了适当的模拟方案。发展了一种高度直观、图形化的超级算符形式，用于计算分子对量子光和随机光的响应，并应用于利用脉冲整形、相位控制和手征偏振构型来产生新型光脉冲序列。研究了旨在通过电子相干和核相干提供锥形交叉点明确光谱特征的新的非线性信号。光的量子性质，如光子纠缠，通过提供经典光无法获得的信息，被用作探测分子和生色团聚集体的额外工具。例如，纠缠和压缩的光子提供了其他方法无法实现的时间和光谱分辨率。探索了将单个纠缠光子的符合测量和干涉测量相结合的探测方案，并将其用于研究光合作用天线和反应中心光收集中的基本电荷和能量迁移过程。预测了具有时间和光谱门控的多光子符合信号。计算了光子统计测量和高阶辐射场关联函数，为分子动力学过程提供了新的光谱工具。发展和研究了利用荧光或电流对相干光信号进行非相干检测的方案，这种方案非常灵敏，可以用于单分子的研究。

Shaul Mukamel, of the University of California, Irvine is supported by an award from the Chemical Theory, Models and Computational Methods program in the Division of Chemistry. Mukamel and his coworkers design cutting-edge spectroscopy experiments and develop models and methods for interpreting the results. Understanding and controlling the motions of electrons and nuclei in molecules can determine the rates and outcomes of chemical reactions and energy transfer processes. These include the conversion of solar energy into electric energy in natural photosynthesis and in artificial light harvesting devices. This program develops methods for studying these elementary events by measuring the response of complex molecules to sequences of ultrafast optical laser pulses. Such experiments are made possible by newly-developed laser sources. Models and practical computational tools are developed for the interpretation and analysis of these experiments and extracting the underlying molecular information. Professor Mukamel and his research group collaborate closely with leading experimental research groups all over the world.Novel experimental techniques involving carefully-timed pulse sequences are designed and broadly applied to molecules and molecular aggregates as well as in the condensed phase. Spectroscopic techniques that aim at the direct detection of electronic and vibrational coherence, as well as nonadiabatic dynamics where the Born Oppenheimer approximation breaks down, are developed. Broadband resonant and off-resonant Raman techniques that can directly probe the passage of molecules through conical intersections are designed, and adequate protocols for their simulation are developed. A highly-intuitive, diagrammatic superoperator formalism is developed for computing the response of molecules to quantum and stochastic light and applied towards creating novel optical pulse sequences by utilizing pulse shaping, phase control, and chiral polarization configurations. New nonlinear signals aimed at providing unambiguous spectroscopic signatures of conical intersections through electronic and nuclear coherences are investigated. The quantum properties of light, such as photon entanglement are used as additional tools for probing molecules and chromophore aggregates by providing information that is not accessible by classical light. For example, entangled and squeezed photons offer temporal and spectral resolutions not achievable by other means. Detection schemes that combine coincidence measurements of individual entangled photons and interferometry are explored and used to investigate the elementary charge and energy migration processes in light harvesting in photosynthetic antennae and reaction centers. Signals involving multiple photon coincidence with temporal and spectral gating are predicted. Photon statistics measurements and higher-order radiation field correlation functions are calculated and shown to provide novel spectroscopic tools for molecular dynamical processes. Incoherent detection schemes of coherent optical signals by fluorescence or electric currents, which are very sensitive and can allow the study of single molecules are developed and investigated.