Light Induced Processes in the Condensed Phase

凝聚相中的光诱导过程

• 批准号: 9421043
• 负责人: Robin Hochstrasser
• 金额: --
• 依托单位: University of Pennsylvania
• 依托单位国家: 美国
• 项目类别: Continuing grant
• 财政年份: 1995
• 资助国家: 美国
• 起止时间: 1995-02-01 至 1998-11-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9421043&HistoricalAwards=false
• 关键词: Light; Induced; Processes; Condensed; Phase

9421043 Hochstrasser This research is focused on two main areas arising from recent technological advances in optical and infrared femtosecond pulse generation and near-field microscopy. Linear and nonlinear infrared properties of materials in the teraherz and the vibrational fundamental region are now accessible with time resolution in the 40-160 fs regime. These methods will be used to determine directly the nuclear responses, over a wide frequency range, to charge reorganization in conjugated polymers, charge transfer complexes and their crystals. Impulsive excitations of the nuclear motions leads to wavepackets whose motion in time can be used to characterize the potential surfaces involved. The vibrational energy dynamics also will be studied directly. A complete study of the higher exciton states of materials with confined excitations on linear chains of polysilanes will be conducted to understand the excited states of such chains in which the electron and hole are more separated. The second area of the proposed research is concerned with the dynamics and electronic properties of organic nanoscale systems using near-field methods. The materials to be characterized include: self assembled monolayers of proteins (on semiconductors) that can undergo energy and electron transfer with single protein spatial resolution; polysilane films and stretched films in which linear chain excitations can be separately examined; aggregates of cyanine dyes having coherence lengths larger than the tip size of the near-field microscope; and organic nanoparticles that can be separately examined and their confinement properties characterized. %%% The proposed research is in two main areas arising from our recent technological advances in optical and infrared femtosecond pulse generation and near-field microscopy. The first involves characterization of the femtosecond vibrational and electronic responses of materials in the infrared region of the spectrum from close to zero frequency to 8000 cm-1. The second is the determination of optical properties of nanoscopic and low dimensional organic, bio and polymeric materials by means of the newly developed near- field picosecond time resolved microscopy. This work is important because: 1) infrared properties of materials, particularly organic and biomaterial are not widely explored yet, and 2) it allows examining nanoenvironment in materials on the scale of single, isolated molecule.

小行星9421043 这项研究的重点是两个主要领域所产生的最新技术进步，在光学和红外飞秒脉冲产生和近场显微镜。 材料在太赫兹和振动基本区域的线性和非线性红外特性现在可以在40-160 fs范围内获得时间分辨率。 这些方法将用于在宽的频率范围内直接测定共轭聚合物、电荷转移络合物及其晶体中电荷重组的核响应。核运动的脉冲激发导致波包，其随时间的运动可以用来表征所涉及的势面。 振动能量动力学也将直接研究。将对聚硅烷线性链上具有受限激发的材料的更高激子态进行完整的研究，以了解电子和空穴更加分离的这种链的激发态。拟议研究的第二个领域是使用近场方法的有机纳米系统的动力学和电子特性。待表征的材料包括：蛋白质的自组装单层（在半导体上）可以以单一蛋白质空间分辨率进行能量和电子转移;聚硅烷膜和拉伸膜，其中可以分别检查线性链激发;相干长度大于近场显微镜尖端尺寸的花青染料聚集体;和有机纳米颗粒，可以单独检查和它们的限制特性的特点。 拟议的研究是在两个主要领域所产生的，从我们最近的技术进步，在光学和红外飞秒脉冲产生和近场显微镜。第一个涉及表征的飞秒振动和电子响应的材料在光谱的红外区域从接近零频率到8000 cm-1。二是利用新发展的近场皮秒时间分辨显微术测定纳米级和低维有机、生物和聚合物材料的光学性质。这项工作很重要，因为：1）材料，特别是有机和生物材料的红外特性尚未被广泛探索，2）它允许在单个孤立分子的尺度上检查材料中的纳米环境。