权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

Study of electronic excited states of molecule absorbed surface by nonlinear spectroscopy

非线性光谱研究分子吸收表面电子激发态

基本信息

批准号：
12640488
负责人：
ONDA Ken
金额：
$ 1.98万
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 (C)
财政年份：
2000
资助国家：
日本
起止时间：
2000 至 2001
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-12640488/
关键词：
Second Harmonic Generation surface electronic excited state Cu(111)Ni(111)benzene formate CO 電子将起状態

项目摘要

In this research, electronic excited states of molecule adsorbed surfaces were studied by nonlinear spectroscopy, such as second harmonic generation (SHG) spectroscopy and sum frequency generation (SFG) spectroscopy. On benzene or CO adsorbed Cu(111) surfaces, SHG spectra of SH wavelength region from 250 nm to 700 nm were measured using femtosecond tunable laser system based on a Ti:sapphire regenerative amplifier system. The new electronic resonance peaks on the clean Cu(111) surface were found on the spectra. One of the peaks was assigned to the resonances between the electronic state on the defect sites and the other peak was assigned to the electronic state which is peculiar to the surface with sub-monolayer benzene adsorption. Time-resolved vibrational measurements were carried out on formate (HCOO) adsorbed on Ni(111) surface by combining the sum-frequency generation (SFG) method and picosecond laser system (time-resolution of 6 ps). Rapid intensity decreas (within the time-resolution) followed by intensity recovery (time-constant of several 10s ps) of CH stretching signal was observed when picosecond 800 nm pulse was irradiated on the sample surface. From the results of temperature and pump fluence dependences of temporal behavior of signal intensity, we concluded that the observed intensity change was induced by non-thermal process.

本研究利用二次谐波(SHG)光谱和和频(SFG)光谱等非线性光谱方法研究了分子吸附表面的电子激发态。利用基于钛宝石再生放大系统的飞秒可调谐激光系统，在苯或CO吸附的铜(111)表面，测量了250~700 nm SH波长范围内的倍频光谱。在清洁的Cu(111)表面上发现了新的电子共振峰。其中一个峰归属于缺陷位上电子态之间的共振，另一个峰归属于亚单层苯吸附表面所特有的电子态。用和频(SFG)方法和皮秒激光系统(时间分辨率为6ps)相结合，对吸附在Ni(111)表面的甲酸盐(HCOO)进行了时间分辨振动测量。当800 nm脉冲照射到样品表面时，观察到CH展宽信号的强度迅速衰减(在时间分辨率范围内)和强度恢复(时间常数为10s ps)。从信号强度随时间变化的温度和泵浦能量依赖关系的结果可以看出，观测到的强度变化是由非热过程引起的。