Time-Resolved Photoelectron Spectroscopy: Probing Nonadiabatic Dynamics in Polyatomic Molecules

时间分辨光电子能谱：探测多原子分子的非绝热动力学

• 批准号: 0956610
• 负责人: Vincent McKoy
• 金额: $ 25.5万
• 依托单位: California Institute of Technology
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-09-01 至 2014-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0956610&HistoricalAwards=false
• 关键词: Time; Resolved; Photoelectron; Spectroscopy; Probing

In this project supported by the Chemical Structure, Dynamics, and Mechanisms Program of the Division of Chemistry, Professor Vincent McKoy and his research group at the California Institute of Technology will develop quantum mechanical methods for simulating femtosecond time-resolved photoelectron spectroscopy (TR-PES) data. TRPES is a technique that can reveal the internal dynamics of a molecule, including the motion of atoms and changes in electronic structure when the molecule is excited by light. The focus of this research will be on non-adiabatic dynamics, especially conical intersections responsible for internal conversion and photodissociation. Because photoionization amplitudes vary rapidly with the nuclear coordinates near conical intersections, calculations that track this geometry dependence are essential to extract the wave-packet dynamics from measured energy- and angle-resolved photoelectron distributions. The research to be undertaken bears directly on understanding the dynamics in polyatomic molecules, including such important issues as the photostability of the DNA nucleobases and the mechanisms by which light-sensitive proteins function. Besides aiding in the design and interpretation of related experiments, therefore, this research also has wide biophysical and biomedical implications. Detailed knowledge of photon interactions with biomolecules may in the long run assist in developing, for example, biomimetic photosensitive systems or genotoxic phototherapies for cancer. By providing a context for training younger researchers in theoretical molecular photoelectron spectroscopy, moreover, this research project addresses a critical need, since there are very few theorists worldwide to support the many experimental groups active in this field. The research will be carried out within longstanding, productive, and mutually beneficial collaborations with research groups in the U.S., Japan, Canada, and Brazil.

在这个由化学系化学结构、动力学和机制计划支持的项目中，文森特·麦考伊教授和他在加州理工学院的研究小组将开发用于模拟飞秒时间分辨光电子能谱(TR-PES)数据的量子力学方法。TRPES是一种可以揭示分子内部动力学的技术，包括分子受光激发时原子的运动和电子结构的变化。这项研究的重点将放在非绝热动力学，特别是负责内转换和光解的锥形交叉口。由于光致电离幅度随锥形交点附近的原子核坐标快速变化，跟踪这种几何关系的计算对于从测量的能量和角度分辨的光电子分布中提取波包动力学是至关重要的。将要进行的研究直接关系到对多原子分子动力学的理解，包括DNA核苷酸碱基的光稳定性和光敏蛋白质发挥作用的机制等重要问题。因此，除了有助于相关实验的设计和解释外，本研究还具有广泛的生物物理和生物医学意义。从长远来看，对光子与生物分子相互作用的详细了解可能有助于开发仿生光敏系统或癌症的基因毒性光疗。此外，通过提供培训理论分子光电子能谱方面的年轻研究人员的背景，这一研究项目解决了一个关键需求，因为世界上几乎没有理论家来支持活跃在该领域的许多实验小组。这项研究将在与美国、日本、加拿大和巴西的研究小组长期、富有成效和互惠互利的合作中进行。