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Study of photodesorption dynamics by using pulsive synchrotron radiation

利用脉冲同步辐射研究光解吸动力学

基本信息

批准号：
05452045
负责人：
KAMADA Masao
金额：
$ 4.22万
依托单位：
Okazaki National Institutes
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (B)
财政年份：
1993
资助国家：
日本
起止时间：
1993 至 1995
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-05452045/
关键词：
Photodesorption Time response Surface Dynamics Ionic crystal Alkali atom Excited state alkali LIF 放射光パルス動的過程

项目摘要

The purpose of the present project is to investigate photodesorption dynamics on solid state surfaces. The followings are the results of the present projects :(1) By using synchrotron radiation covering wide energy range and quasi-monochromatic intense undulator radiation, desorption of excited-state alkali atoms were observed in the energy ranges corresponding to the valence and core level excitations. This means that desorption is caused by valence excitation as well as core-level excitation.(2) Temperature, irradiation dose, and substance dependences of the desorption intensities were very different between excited-state alkali atoms and ground state alkali atoms.(3) Time response of the excited-state alkali atoms was successfully observed by using pulsive synchrotron radiation. The time response consisted of a nano-second component and a slow component between micro and milli-seconds, indicating two (fast and slow) desorption mechanisms.(4) Signal of the Laser-Induced-Fluorescence was obtained on ground state potassium atoms from KCl and KBr. By changing the timing between synchrotron radiation and a diode laser, the time response of the ground-state alkali desorption was observed for the first time in the world. Any existing model cannot explain the fast desorption of the ground-state alkali atoms.(5) Photodesorption experiments were carried out in the same chamber as the photoelectron spectrometer to know the effects of the adsorbates on the solid surfaces.

本项目的目的是研究固体表面的光解吸动力学。主要研究结果如下：(1)利用覆盖宽能区的同步辐射和准单色强波动辐射，在与价态和核能级激发相对应的能量范围内观察到了激发态碱原子的脱附现象。(2)激发态碱原子与基态碱原子的脱附强度随温度、辐照剂量和物质的变化有很大的不同。(3)利用脉冲同步辐射成功地观测到激发态碱原子的时间响应。时间响应由一个纳秒分量和一个介于微秒和毫秒之间的慢分量组成，表明了两种(快和慢)的脱附机制。(4)从KCl和KBr的基态钾原子上获得了激光诱导荧光的信号。通过改变同步辐射和半导体激光器之间的时间关系，首次观察到了基态碱解吸的时间响应。现有的任何模型都不能解释基态碱原子的快速脱附。(5)光解吸实验是在与光电子能谱仪相同的小室中进行的，以了解吸附在固体表面上的影响。