Excited State Dynamics

激发态动力学

• 批准号: RGPIN-2015-06730
• 负责人: Schuurman, Michael
• 金额: $ 2.55万
• 依托单位: University of Ottawa
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2019
• 资助国家: 加拿大
• 起止时间: 2019-01-01 至 2020-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=685497
• 关键词: Excited; State; Dynamics

This program employs computational quantum chemical methods to reveal not only how molecules respond on femtosecond timescales to the absorption of a photon of light, but also how this dynamical response may be observed using time-resolved spectroscopic techniques.  Our approach utilizes trajectory simulations in which the time-evolution of the atomic and electronic degrees of freedom of molecules are determined by computing potential energy surfaces 'on-the-fly' using ab initio electronic structure methods.  However, molecular trajectories are not observable quantities; this requires that the molecular wave packet be probed using ultrafast laser pulses.  The ability of high-level simulation to predict the resulting time-resolved spectra unifies theoretical and experiment approaches to unravel the mechanistic details of ultrafast phenomena.  Our group is engaged with a wide network of experimental collaborators, in both academic ultrafast laser labs and advanced light source facilities, to investigate novel methods of interrogating molecular motions on inherent timescales.***The current proposal will employ a total of four NSERC supported students in three main research thrusts: 1) the development of model theories for molecular excited state dynamics, 2) the 'complete simulation' of time-resolved spectroscopic experiments, and 3) investigation of the potential for novel X-ray probes of molecular dynamics.  The first research thrust addresses a persistent gap in our understanding of excited state processes: the lack of descriptive theories and models for excited state processes.  The ultimate goal of running our "simulation machinery" on specifically chosen molecular examples and model systems is the construction of rules governing dynamics involving (conically) intersecting electronic surfaces. The second thrust recognizes that validation of dynamical methods require comparison to experimental results. The most unambiguous comparison to be made is via the direct simulation of experimental observables. Our group is uniquely positioned, both in the simulation toolkit we've developed and in the network of experimental collaborators we employ, to demonstrate the ability of theoretical methods to speak to modern ultrafast experiments.  Lastly, developments in light sources now allow for femtosecond X-ray pulses that may be deployed in ultrafast pump-probe experiments. The wavelengths of X-ray photons is on the order of interatomic distances and promise to yield location specific information on the electronic environment at particular atomic sites in a molecule.  Our aim is to guide the interpretation of these new experiments using our well-positioned techniques. This program will provide students with an opportunity to conduct leading-edge, multidisciplenary research within a global network of theoretical and experimental collaborators.**

该程序采用计算量子化学方法，不仅揭示了分子在飞秒时间尺度上如何响应光光子的吸收，而且还揭示了如何使用时间分辨光谱技术观察这种动态响应，我们的方法利用轨迹模拟，其中。分子的原子和电子自由度的时间演化是通过使用从头算电子结构方法“即时”计算势能面来确定的。然而，分子轨迹却不是。可观察的量；这需要使用超快激光脉冲来探测分子波包，以预测所产生的时间分辨光谱的能力将理论和实验方法结合起来，以揭示超快现象的机制细节。与学术超快激光实验室和先进光源设施中​​的广泛实验合作者网络合作，研究在固有时间尺度上询问分子运动的新方法。***当前的提案将总共采用四个NSERC 支持学生的三个主要研究方向：1) 分子激发态动力学模型理论的发展，2) 时间分辨光谱实验的“完整模拟”，3) 新型 X 射线探针的潜力研究​第一个研究重点解决了我们对激发态过程的理解中持续存在的差距：缺乏激发态过程的描述性理论和模型​在专门选择的分子和模型上运行我们的“模拟机器”的最终目标。系统就是建设第二个推力认识到，需要与实验结果进行比较的动力学方法的验证是通过对实验观测值的直接模拟来进行的。我们开发的模拟工具包以及我们雇用的实验合作者网络，证明了理论方法与现代超快实验对话的能力。最后，光源的发展现在允许飞秒 X 射线。可以在超快泵浦探测实验中使用的脉冲 X 射线光子的波长约为原子间距离，并有望产生分子中特定原子位点的电子环境的特定位置信息。使用我们定位良好的技术指导对这些新实验的解释。该计划将为学生提供在全球理论和实验合作者网络中进行前沿、多学科研究的机会。**