Multiple-Pulse, Single-Shot Femtosecond Spectroscopy of Condensed Phases

凝聚相的多脉冲、单次飞秒光谱

• 批准号: 9404548
• 负责人: Keith Nelson
• 金额: $ 46.03万
• 依托单位: Massachusetts Institute of Technology
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1994
• 资助国家: 美国
• 起止时间: 1994-06-01 至 1998-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9404548&HistoricalAwards=false
• 关键词: Multiple; Pulse; Single; Shot; Femtosecond

In this project in the Physical Chemistry Program of the Chemistry Division, Prof. Keith A. Nelson of the Massachusetts Institute of Technology will engage in a series of continuing investigations in the field of optical control of molecular and material behavior, including structural and chemical rearrangements in condensed media. These studies rely on the use of multiple-pulse femtosecond spectroscopy at visible, near-infrared or near-ultraviolet wavelengths. Shaped femtosecond pulse sequences are to be used to drive large-amplitude vibrations in crystal lattices to enable the spectroscopic observation of far-from-equilibrium crystal geometries. Additional work will concentrate on the development of an automated time-domain vibrational spectrometer, the manipulation of electronic coherences to observe coherent wavepacket dynamics in electronic levels accessible only through two-photon transitions, and other topics. The initial stages of the research will be devoted to the implementation of improved methods for the generation, characterization, and amplification of complex femtosecond waveforms. Current forefront research in physical chemistry includes the study of molecular processes at ultra-short time scales that correspond to the period of one molecular vibration ( a few femtoseconds). These investigations have the potential of providing methods for the control of molecular reactions and other dynamical processes, as well as providing optical analogs of the nuclear magnetic resonance technique to study condensed phase optical spectroscopy.

在化学部的物理化学计划中，马萨诸塞州理工学院的基思·A·尼尔森教授将在分子和材料行为的光学控制领域进行一系列持续研究，包括结构和化学重排在冷凝的媒体中。 这些研究依赖于在可见，近红外或接近粉状的波长处使用多脉冲飞秒光谱。 形状的飞秒脉冲序列应用于在晶体晶格中驱动大振幅振动，以实现远距离平衡晶体几何形状的光谱观察。 额外的工作将集中于自动化时域振动光谱仪的发展，对电子相干的操纵，以观察仅通过两光子过渡可访问的电子水平的相干波袋动力学以及其他主题。 研究的初始阶段将致力于实施改进的复杂飞秒波形的生成，表征和扩增的方法。 当前物理化学方面的最前沿研究包括对与一个分子振动（几次飞秒）时期相对应的超短期时间尺度上的分子过程研究。 这些研究具有为控制分子反应和其他动力学过程的控制的潜力，并提供了核磁共振技术的光学类似物来研究凝结相光谱光谱。