Molecular Radiative and Relaxation Processes

加州大学欧文分校的Shaul Mukamel获得了化学部理论、模型和计算方法项目的支持，以设计、建模和分析相干非线性多维光谱。Liouville空间的超级算符方法正在被开发并用作涉及快速脉冲光与物质相互作用的应用的计算工具：(1)相干和非相干飞秒单分子光谱，包括针尖和结载流接触的非平衡情况，(2)量子场中纠缠光子的多维光谱，(3)分子发色团聚集体和量子点阵列中的电荷分离和多激子光谱特征，以及(4)利用灵活的脉冲极化策略实现分子手性的飞秒相干反斯托克斯拉曼散射探针。这些实验和许多其他实验使用Liouville方法描述，并使用为多维光学、电子和振动光谱学创建的软件Spectron进行计算建模，并向研究界提供。分子对不同光束的响应取决于许多因素，例如光束相互重叠的程度以及分子在空间和时间上的重叠程度。PI已经开发了工具来计算在不同情况下的响应，例如当分子也被扫描隧道显微镜尖端探测时，或者在两个电导线之间携带电流时。每个波束也可以是一系列快速重复的脉冲，丰富了可以诱发的反应的集合。许多最有趣的实验可以用PI创建的方法和软件来模拟，这些实验涉及接近分子样本或从分子样本散射的光子之间特定类型的关联，分子样本甚至可以由单个分子组成。PIS的书《非线性光学原理》是这一领域研究的主要指南，并正在根据该奖项进行广泛的修订。受过这些方法培训的研究人员源源不断地由学生和博士后研究员在PI的指导下产生。

Shaul Mukamel of the University of California Irvine is supported by an award from the Theory, Models and Computational Methods program in the Chemistry Division for the design, modeling and analysis of coherent nonlinear multidimensional spectroscopies. Superoperator approaches in Liouville space are being developed and used as computational tools for applications involving interactions of fast-pulsed light and matter: (1) Coherent and incoherent femtosecond single-molecule spectroscopy, including non-equilibrium circumstances with tip and junction current-carrying contacts, (2) multidimensional spectroscopy with entangled photons of quantum fields , (3) charge separation and multi-exciton spectroscopic signatures in molecular chromophore aggregates and quantum dot arrays, and (4) femtosecond coherent anti-Stokes Raman scattering probes of molecular chirality using flexible pulse-polarization strategies. These and numerous other experiments are described using the Liouville approach, and computationally modeled using software SPECTRON created for multidimensional optical electronic and vibrational spectroscopy and made available to the research community. The response of a molecule to different light beams depends on many factors, such as how much the beams overlap with each other and the molecule in both space and time. The PI has developed the tools to calculate the responses under different circumstances, such as when the molecule is also being probed by a scanning tunneling microscope tip or is carrying current between two electrical leads. Each beam can also be a series of pulses repeated very quickly, enriching the collection of responses that can be evoked. Many of the most interesting experiments that can be simulated using the methods and software created by the PI involve definite types of correlations between photons approaching or scattering from the molecular sample, which can consist of even a single molecule. The PIs book "The Principles of Nonlinear Optics" is the principal guidebook for research in this community and is undergoing extensive revision under this award. A steady flow of researchers trained in these methods is produced by the students and postdoctoral fellows mentored by the PI.