State-to-State Photodissociation of Polyatomic Free Radicals: Nonadiabatic Dynamics and Quantum Coherence

多原子自由基的状态到状态光解离：非绝热动力学和量子相干性

• 批准号: 2155232
• 负责人: Jingsong Zhang
• 金额: $ 46.37万
• 依托单位: University of California-Riverside
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-09-01 至 2025-08-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2155232&HistoricalAwards=false
• 关键词: State; Photodissociation; Polyatomic; Free; Radicals

The Chemical Structure, Dynamics and Mechanisms A (CSDM-A) program of the Chemistry Division funds Professor Jingsong Zhang of the University of California at Riverside to investigate the photodissociation dynamics of polyatomic free radicals. Free radicals are important reactive intermediates in many chemical environments (such as combustion and atmospheric chemistry). This research aims to understand the photochemistry of polyatomic radicals and the roles of interacting electronic states with quantum accuracy. The knowledge (free radical electronic structures, energetics, reaction mechanisms, etc.) from this project is valuable to the combustion, atmospheric chemistry, theoretical chemistry, and physics communities. The project trains graduate students and prepares them for careers in academia or industry and promotes research experience of women and underrepresented minority undergraduate students. The project reaches out to the diverse student population in the Riverside and San Bernardino community colleges. This program also mentors economically disadvantaged high school students for summer research internships.The project focuses on the hydroxymethyl, hydroperoxy, and methylene radicals. Experimentally, the free radicals are produced by photolysis of suitable precursors and subsequent reactions and are cooled in a molecular beam with a well-defined initial energy. The free radicals are photodissociated under a single collision condition by tunable laser radiation, producing hydrogen atom photoproducts. The high-n Rydberg atom time-of-flight technique is utilized to measure state-resolved product kinetic energy and angular distributions. These distributions are closely related to theoretical calculations and are central to understanding photodissociation dynamics and mechanisms. The research generates high-quality data and benchmarks to test quantum mechanical theories of the excited open-shell species.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

化学系的化学结构、动力学和机理A(CSDM-A)计划资助加州大学河滨分校的张静松教授研究多原子自由基的光解离动力学。自由基是许多化学环境(如燃烧和大气化学)中重要的活性中间体。这项研究旨在了解多原子自由基的光化学以及相互作用电子态在量子精确度中的作用。知识(自由基电子结构、能量学、反应机理等)该项目对燃烧、大气化学、理论化学和物理学界具有重要价值。该项目培训研究生，为他们在学术界或工业界的职业生涯做好准备，并促进女性和代表不足的少数族裔本科生的研究经验。该项目覆盖了河滨大学和圣贝纳迪诺社区大学的不同学生群体。该计划还指导经济困难的高中生进行暑期研究实习。该项目侧重于羟甲基、氢过氧基和亚甲基自由基。在实验上，自由基是由合适的前体光解和随后的反应产生的，并在具有明确初始能量的分子束中冷却。在单次碰撞条件下，通过可调谐激光辐射，自由基被光解离，产生氢原子光产物。高n里德堡原子飞行时间技术被用来测量状态分辨的产物动能和角分布。这些分布与理论计算密切相关，是理解光解动力学和机理的核心。这项研究产生了高质量的数据和基准来测试兴奋的开壳物种的量子力学理论。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

项目成果

Thermal Decomposition Mechanism of Tetraethylsilane by Flash Pyrolysis Vacuum Ultraviolet Photoionization Mass Spectrometry and DFT Calculations: The Competition between β-Hydride Elimination and Bond Homolysis

四乙基硅烷的快速热解真空紫外光电离质谱和 DFT 计算的热分解机理：β-氢化物消除与键均质分解之间的竞争

• DOI: 10.1021/acs.jpca.2c09081
• 发表时间: 2023
• 期刊: The Journal of Physical Chemistry A
• 作者: Shao, Kuanliang;Liu, Xinghua;Zhang, Jingsong
• 通讯作者: Zhang, Jingsong

Flash pyrolysis mechanism of trimethylchlorosilane

三甲基氯硅烷闪蒸热解机理

• DOI: 10.1016/j.ijms.2022.116933
• 发表时间: 2022
• 期刊: International Journal of Mass Spectrometry
• 影响因子: 1.8
• 作者: Shao, Kuanliang;Brunson, Jonah;Tian, Yi;Zhang, Jingsong
• 通讯作者: Zhang, Jingsong

Two-photon dissociation dynamics of the mercapto radical

巯基自由基的双光子解离动力学

• DOI: 10.1039/d2cp04116b
• 发表时间: 2022
• 期刊: Physical Chemistry Chemical Physics
• 影响因子: 3.3
• 作者: Qin, Yuan;Zheng, Xianfeng;Song, Yu;Sun, Ge;Zhang, Jingsong
• 通讯作者: Zhang, Jingsong

Flash pyrolysis vacuum ultraviolet photoionization mass spectrometry of cycloheptane: A study of the initial decomposition mechanism

• DOI: 10.1177/14690667221142699
• 发表时间: 2022-12
• 期刊: European Journal of Mass Spectrometry
• 影响因子: 1.3
• 作者: Kuanliang Shao;Ge Sun;Mariah Gomez;Xinghua Liu;Jingsong Zhang

Low-Pressure and Nascent Yields of Thermalized Criegee Intermediate in Ozonolysis of Ethene

乙烯臭氧分解热化 Criegee 中间体的低压和初期产率

• DOI: 10.1021/acs.jpclett.2c02940
• 发表时间: 2022
• 期刊: The Journal of Physical Chemistry Letters
• 作者: Yang, Lei;Campos-Pineda, Mixtli;Zhang, Jingsong
• 通讯作者: Zhang, Jingsong