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Dynamics of surface electronic excited states

表面电子激发态动力学

基本信息

批准号：
08404039
负责人：
HIROSE Chiaki
金额：
$ 25.73万
依托单位：
TOKYO INSTITUTE OF TECHNOLOGY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (A)
财政年份：
1996
资助国家：
日本
起止时间：
1996 至 1998
项目状态：
已结题

项目摘要

1. Time-resolved SFG observation of transient behavior of CO adsorbed on Ni(111) and NiO(111) surfacesTransient SFG spectra on CO/Ni(111) and CO/NiO(111) systems under the irradiation by UV and visible picosecond laser pulses as the excitation pulse was measured. It was found that the transient vibrational hand with the lifetime shorter than 30 ps was appeared when the UV pulses was irradiated. The results suggest that the substrate hot electrons generated by the UV pulses could excite the CO stretching vibrational mode by electronic driven process.2. Time-resolved SFG study of short-lived surface species produced by the intense NIR pulsesTransient species on the formate adsorbed Ni(111) and NiO(111) surfaces produced by the temporal temperature increase due to the picosecond NIR pulse irradiation was observed by the time-resolved SFG method. It was found that the unstable monodentate formate was appeared as the intermediates of the decomposition reaction.3. Relaxation dynamics of the … More water molecule adsorbed on the zeolite OH groups.The vibrational lifetimes of the species adsorbed on the zeolite OH group was measured by the picosecond IR pump-probe method. The IVR process in the adsorbed water molecule followed by the energy relaxation process to the low-frequency phonon mode of zeolite framework was observed, and the vibrational lifetimes were measured.4. Excimer lifetime of naphthalene adsorbed on Ni(111) surfaceThe thickness dependence of lifetime of fluorescence from the naphthalene films adsorbed on Ni(111) surface was measured. The lifetime showed the strong thickness dependence when the thickness was less than 50 nm due to the image dipole interaction between the naphthalene excimer and Ni surface.5. SHG measurements of the electronic excited states on benzene and naphthalene adsorbed Cu(111) surfaceResonant SHG spectra were measured on the benzene/Cu(111) and naphthalene/Cu(111) systems. For both cases, the resonant peaks showed the blue shifts compared with the resonant frequency of free molecules due to the interaction between the excited states of the molecules and the surface state of Cu(111) surface.6. Hot electron dynamics of CdO thin filmFemtosecond pump-probe experiments were carried out on the heavily doped n-type CdO thin film. It was observed that the thermalization process of hot electrons generated by the UV femtosecond pulses, and the time constant of electron-lattice thermalization was estimated as 22 ps at the substrate temperature of 30K. Less

1. CO在Ni（111）和NiO（111）表面吸附瞬态行为的时间分辨SFG观测采用紫外皮秒激光脉冲和可见光皮秒激光脉冲作为激发脉冲，测量了CO/Ni（111）和CO/NiO（111）体系的瞬时SFG光谱。结果表明，在紫外脉冲照射下，出现了寿命小于30ps的瞬态振动手。结果表明，紫外脉冲产生的衬底热电子可以通过电子驱动过程激发CO拉伸振动模式。用时间分辨SFG方法观察了近红外脉冲照射后，甲酸盐吸附的Ni（111）和NiO（111）表面由于时间升温而产生的瞬态物质。结果表明，分解反应的中间产物为不稳定的单齿甲酸酯。沸石羟基吸附水分子的弛豫动力学。采用皮秒红外泵浦探针法测定了吸附在沸石OH基团上的物质的振动寿命。观察了吸附水分子的IVR过程，然后观察了能量弛豫过程到沸石骨架的低频声子模式，并测量了振动寿命。测定了吸附在Ni（111）表面的萘膜的荧光寿命与厚度的关系。当厚度小于50 nm时，由于萘准分子与Ni表面的图像偶极相互作用，寿命表现出较强的厚度依赖性。在苯/Cu（111）和萘/Cu（111）体系上测量了电子激发态的共振SHG谱。在这两种情况下，由于分子激发态与Cu（111）表面态的相互作用，共振峰与自由分子的共振频率相比出现了蓝移。在重掺杂n型CdO薄膜上进行了飞秒泵浦探针实验。观察了紫外飞秒脉冲产生的热电子的热化过程，估计了基片温度为30K时电子-晶格热化的时间常数为22 ps。少