Femtosecond IR Probe of Ultrafast Dynamics of Molecular Adsorbates on Nanoparticles: Solvation and Electron Transfer

纳米颗粒上分子吸附物超快动力学的飞秒红外探针：溶剂化和电子转移

• 批准号: 0135427
• 负责人: Tianquan Lian
• 金额: $ 31.24万
• 依托单位: Emory University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-05-01 至 2005-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0135427&HistoricalAwards=false
• 关键词: Femtosecond; IR; Probe; Ultrafast; Dynamics

Dr. Tianquan Lian of Emory University is funded for his research on femtosecond IR probe of ultrafast dynamics of molecular adsorbates on nanoparticles - solvation by a grant in the Physical Chemistry program of the Chemistry Division. He will further develop and test the theory of solvation-induced vibrational peak shift and use this novel approach to study solvation dynamics of molecules at nanoparticle/liquid interfaces. For molecules with large dipole moment changes between ground and excited states, femtosecond excitation prepares the excited molecule in a non-equilibrium solvent configuration. The effect of the subsequent solvation on solute vibrational spectra is not yet understood, unlike the well-studied effect on solute electronic spectra. He is developing a theory of solvation-induced solute dynamic vibrational peak shift based on the Onsager dielectric continuum model of solvent-solute interaction. Dynamic peak shifts will be measured in Re(dcbpy)(CO)3Cl and related molecules in different solvents. The magnitude and dynamics of the CO stretching peak shifts will be used to compare with and critically test the theoretical model. He also will use vibrational peak shift as a new method to study solvation dynamics at solid-liquid interfaces. The combination of IR probe and nanocrystalline films will allow the study of solvation dynamics in a wide range of solvents. This approach is complementary to existing techniques such as fluorescence Stokes shift and the optical Kerr effect, and may have unique applications in slightly scattering media such as nanocrystalline thin films, that are difficult to study using these extant techniques. The proposed research is a continuation of Dr. Lian's research effort in understanding ultrafast dynamics of molecular adsorbates on nanoparticles. Semiconductor and metal nanoparticles have many potential applications ranging from nanoelectronics, solar energy conversion, to biomedical-imaging. Most nanoparticles are synthesized or modified with attached molecules as passivating, structural linkage, sensitizing, or molecular sensing groups. These molecules play essential roles in transfer, transport and dissipation of charge and energy in these systems. The proposed work will lead to a fundamental understanding of the dynamics of molecules on the nanoparticle surface, such as solvation and energy relaxation. This knowledge is essential to developing more efficient devices based on nanoparticles. The proposed research will also allow the training of postdoctoral fellows, graduate students and undergraduate students in the area of nanoscience and nanotechnology, educating the workforce of the future.

埃默里大学的Tianquan Lian博士获得化学系物理化学项目的资助，用于研究纳米颗粒上分子吸附物的超快动力学-溶剂化的飞秒红外探针。他将进一步发展和测试溶剂化诱导的振动峰位移理论，并使用这种新方法来研究纳米颗粒/液体界面上分子的溶剂化动力学。对于在基态和激发态之间具有大的偶极矩变化的分子，飞秒激发在非平衡溶剂配置中制备激发分子。随后的溶剂化对溶质振动光谱的影响尚未被理解，不像溶质电子光谱的充分研究的效果。他正在开发一种基于溶剂-溶质相互作用的Onsager介电连续模型的溶剂化诱导的溶质动态振动峰位移理论。动态峰位移将在Re（dcbpy）（CO）3Cl和相关分子在不同的溶剂中测量。CO伸缩峰位移的幅度和动力学将用于比较和严格测试的理论模型。他还将利用振动峰位移作为一种新的方法来研究固液界面的溶剂化动力学。红外探针和纳米晶薄膜的组合将允许在广泛的溶剂中的溶剂化动力学的研究。这种方法是现有技术的补充，如荧光斯托克斯位移和光学克尔效应，并可能有独特的应用在轻微的散射介质，如纳米晶体薄膜，这是很难研究使用这些现存的技术。 拟议的研究是Lian博士在理解纳米颗粒上分子吸附物的超快动力学方面的研究工作的延续。半导体和金属纳米粒子具有许多潜在的应用，从纳米电子学，太阳能转换，生物医学成像。大多数纳米颗粒是合成的或修饰的，附着分子作为钝化，结构连接，敏化或分子传感基团。这些分子在这些系统中的电荷和能量的转移、运输和耗散中起着重要作用。拟议的工作将导致对纳米颗粒表面分子动力学的基本理解，如溶剂化和能量弛豫。这些知识对于开发基于纳米颗粒的更有效的设备至关重要。拟议的研究还将允许在纳米科学和纳米技术领域培训博士后研究员，研究生和本科生，教育未来的劳动力。