A New Effect in Ultrafast X-ray Scattering

超快X射线散射的新效应

• 批准号: EP/V049240/1
• 负责人: Adam Kirrander
• 金额: $ 78.02万
• 依托单位: University of Edinburgh
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2021
• 资助国家: 英国
• 起止时间: 2021 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=EP%2FV049240%2F1
• 关键词: New; Effect; Ultrafast; ray; Scattering

Light triggers many important chemical reactions. These include photosynthesis (converting sunlight to chemical energy), human vision (detecting photons via light-induced changes in molecules), and new technologies such as photodynamic therapy for cancer, photocatalysis, fluorescent tags for healthcare diagnostics, and photovoltaics. Light-triggered processes in molecules are difficult to study experimentally and involve a complex interplay of concerted changes in molecular structure and rapid rearrangements of the electrons in the molecule. Conical intersections play a decisive role for the outcome of photochemical reactions, analogous to that of a transition state in standard ground-state chemistry. These are regions on photochemical pathways where molecules can transition efficiently between electronic states. Being able to map the path of molecules through conical intersections would open avenues to controlling photochemical reactivity via modification of excited state dynamics. To achieve this we must simultaneously observe the electronic characteristics of the molecule and the corresponding changes in molecular structure. The challenge is compounded by the short timescales involved, on the order of femtoseconds. Notably, there are as many femtoseconds in a second as there are seconds in 30 million years. In contrast, standard techniques for structural determination require long observation times. New facilities known as X-ray Free-Electron Lasers (XFELs) deliver extremely short pulses of intense high-energy x-ray photons, making completely new types of measurements possible. In recent work, we have demonstrated that we can track the changes in molecular structure in excited molecules and, in separate experiments, detect the nearly instantaneous re-arrangement of electrons when molecules absorb light. Exploiting these advances, the proposed project will develop measurements that track the motion of electrons alongside the motion of the nuclei, allowing conical intersections to be identified, and the structure of molecules at conical intersections to be determined. The resulting experimental technique will yield a powerful tool for fundamental research and provide images of electrons and nuclei that can be used to customise photoactive molecules, ultimately contributing to new technologies in catalysis, new cancer treatments, and energy harvesting from sunlight.

光触发许多重要的化学反应。其中包括光合作用（将阳光转化为化学能），人类视觉（通过光诱导的分子变化检测光子）以及新技术，例如用于癌症的光动力疗法，光催化，医疗保健诊断的荧光标签和光伏电视。分子中的光触发过程很难在实验上研究，并且涉及分子结构的一致变化和分子中电子快速重排的复杂相互作用。圆锥形交叉口对光化学反应的结果起决定性作用，类似于标准基态化学中的过渡态。这些是光化学途径上的区域，分子可以在电子状态之间有效过渡。能够通过圆锥形交叉点绘制分子的路径将通过修改激发态动力学来控制光化学反应性的途径。为了实现这一目标，我们必须同时观察分子的电子特性以及分子结构的相应变化。涉及的短时间尺寸在飞秒阶的顺序中加剧了挑战。值得注意的是，在一秒钟内，有很多人的飞秒与3000万年的几秒钟。相反，结构确定的标准技术需要长时间的观察时间。新设施称为X射线自由电子激光器（XFELS）提供了非常短的高能量X射线光子的极短脉冲，从而使全新的测量结果成为可能。在最近的工作中，我们已经证明，我们可以跟踪激发分子中分子结构的变化，并且在单独的实验中，当分子吸收光线时，可以检测到电子的几乎瞬时重新排列。利用这些进步，提出的项目将开发测量值，以跟踪电子与核的运动一起运动，允许识别圆锥形的交叉点，并确定圆锥形交集处分子的结构。所得的实验技术将产生一种强大的基础研究工具，并提供可用于自定义光活性分子的电子和核图像，最终为催化，新的癌症治疗，新的癌症处理和从阳光收获的能量收获的新技术。

项目成果

Heavy Rydberg and ion-pair states: chemistry, spectroscopy and theory

重里德伯态和离子对态：化学、光谱学和理论

• DOI: 10.1080/0144235x.2022.2077024
• 发表时间: 2022
• 期刊: International Reviews in Physical Chemistry
• 影响因子: 6.1
• 作者: Donovan R

Preface.

前言。

• DOI: 10.1016/s1877-1173(16)30035-7
• 发表时间: 2016
• 期刊: Progress in molecular biology and translational science
• 作者: Shenoy,SudhaK

Brighter, faster, stronger: ultrafast scattering of free molecules

• DOI: 10.1080/23746149.2022.2126796
• 发表时间: 2023-12-31
• 期刊: ADVANCES IN PHYSICS-X
• 影响因子: 6
• 作者: Odate，Asami;Kirrander，Adam;Minitti，Michael P.
• 通讯作者: Minitti，Michael P.

Highlights from Faraday Discussion 228: time resolved imaging of photo-induced dynamics.

法拉第讨论 228 的要点：光致动力学的时间分辨成像。

• DOI: 10.1039/d1cc90220b
• 发表时间: 2021
• 期刊: Chemical communications (Cambridge, England)
• 作者: Dixit G