Attosecond Electron Dynamics

阿秒电子动力学

• 批准号: 2243756
• 负责人: Stephen Leone
• 金额: $ 67.5万
• 依托单位: University of California-Berkeley
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-03-01 至 2026-02-28
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2243756&HistoricalAwards=false
• 关键词: Attosecond; Electron; Dynamics

With support from the Chemical Structure, Dynamics, and Mechanisms-A (CSDM-A) Program in the Division of Chemistry, Professor Stephen Leone of the University of California, Berkeley, is using sophisticated laser techniques to study some of the shortest time processes in molecules. Short time measurements can only be accomplished by first creating X-ray pulses on time frames of one billion billionth of a second, namely one attosecond. This is achieved with laboratory table-top optical methods, producing multiple time-delayed laser pulses to first prepare, then initialize, and finally measure the time dynamics. Professor Leone and his students will analyze the rapid switching of charge from one part of a molecule to another and the extremely fast ensuing chemical transformations with site-specific characterization. Benefits to society arise through the fundamental elucidation of charge flow in molecules that is essential to the conversion of solar energy to electrical output and from the technical training of the future workforce in measurement science and experimental physical chemistry. The Leone group plans to engage middle school and high school teachers to participate in summer research and them team also plans to host high school students on guided visits to these ultrafast spectroscopy laboratories.Attosecond transient absorption in the X-ray is employed for time-resolved dynamics measurements that separate the electron dynamical timescales from those of nuclear motion. Core level spectroscopic transitions in reporter atoms are used. These are charge- and oxidation-state specific, bond-length-sensitive, and electronic-state-dependent, providing a site-selective probe of few-femtosecond time dynamics. Professor Leone and his group are studying attosecond time-resolved processes associated with charge transfer, charge migration, ion pair states, and electronic quantum state superpositions. Attosecond probe pulses are produced via the process of high harmonic generation using few-femtosecond driver laser pulses, and, under this award, three pulse experiments will be developed, to prepare, initialize, and probe, with high state specificity. Broader scientific impacts include the potential to develop tools that push the limits of time, particularly important tools as the dimensions and speed of devices decrease and computing architectures begin to become governed by quantum principles.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.

在化学系化学结构、动力学和机制-A（CSDM-A）项目的支持下，加州大学伯克利分校的斯蒂芬·莱昂教授正在使用复杂的激光技术研究分子中一些最短时间的过程。短时间测量只能通过首先在十亿分之一秒的时间帧上产生X射线脉冲来实现，即一阿秒。这是通过实验室桌面光学方法实现的，产生多个时间延迟的激光脉冲，首先准备，然后初始化，最后测量时间动态。Leone教授和他的学生将分析电荷从分子的一部分到另一部分的快速切换，以及随后发生的具有特定位点特征的极快化学转化。通过从根本上阐明分子中的电荷流（这对将太阳能转换为电力输出至关重要），以及通过对未来劳动力进行测量科学和实验物理化学方面的技术培训，为社会带来了好处。Leone小组计划邀请中学和高中教师参加暑期研究，他们的团队还计划邀请高中学生在指导下参观这些超快光谱实验室。X射线中的阿秒瞬态吸收用于时间分辨动力学测量，将电子动力学时间尺度与核运动的时间尺度分开。使用报告原子中的核心能级光谱跃迁。这些都是电荷和氧化状态的具体，键长敏感，和电子状态的依赖，提供了一个网站选择性探针的几个飞秒的时间动力学。Leone教授和他的团队正在研究与电荷转移、电荷迁移、离子对态和电子量子态叠加相关的阿秒时间分辨过程。阿秒探测脉冲是通过使用几个飞秒驱动器激光脉冲的高次谐波产生过程产生的，根据该奖项，将开发三个脉冲实验，以准备，初始化和探测，具有高状态特异性。更广泛的科学影响包括开发突破时间限制的工具的潜力，特别是随着设备尺寸和速度的减小以及计算架构开始受量子原理支配的重要工具。该奖项反映了NSF的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估而被认为值得支持。

项目成果

Nonresonant coherent amplitude transfer in attosecond four-wave-mixing spectroscopy

阿秒四波混频光谱中的非共振相干振幅传递

• DOI: 10.1103/physreva.107.023526
• 发表时间: 2023
• 期刊: Physical Review A
• 影响因子: 2.9
• 作者: Gaynor, James D.;Fidler, Ashley P.;Kobayashi, Yuki;Lin, Yen-Cheng;Keenan, Clare L.;Neumark, Daniel M.;Leone, Stephen R.
• 通讯作者: Leone, Stephen R.

Core-excited states of SF6 probed with soft-x-ray femtosecond transient absorption of vibrational wave packets

• DOI: 10.1103/physreva.108.012805
• 发表时间: 2023-07-10
• 期刊: PHYSICAL REVIEW A
• 影响因子: 2.9
• 作者: Barreau，Lou;Ross，Andrew D.;Leone，Stephen R.
• 通讯作者: Leone，Stephen R.