Study on the Interaction of Polarized Atomic Hydrogen Beam with Solid Surfaces

本项目的主要课题是开发和应用新的实验技术来研究原子和分子与固体表面的磁相互作用。本项目所开发的技术分为以下三个项目：1。研究了高强度原子氢束的产生和散射原子氢束的探测。原子氢是在射频放电管中形成的，它的自旋态是用六极磁铁来选择的。为了使氢原子的聚焦与它的能量无关，我们开发了一种磁体系统的线性翻译器。原子氢的探测是用热敏电阻装置进行的。研究了其运行条件及其局限性。在几种温度下，对原子氢在石墨表面的反应散射进行了初步测量。为了将束箔光谱技术应用于吸附原子极化的测量，研究了强脉冲激光照射下吸附原子的电离过程。新提出了一种评价电离原子绝对强度的方法，称为“电导调制法”。吸附氢分子邻对转化的测定。用低能电子损失谱法测量了氢的旋转激发。测定了Ag（111）、Xe/Ag（111）、O^2/Ag（111）等几种表面的转化率。

Main subject of this project is the development and application of novel experimental techniques for the study of magnetic interaction of atoms and molecules with solid surfaces. The techniques developed in the project is divided into following three items.1. Atomic beam scattering of polarized atomic hydrogen The generation of high intensity atomic hydrogen beam and the detection of scattered atomic hydrogen were studied. Atomic hydrogen was evolved in a RF discharge-tube and the selection of its spin state was made by using a hexapole magnet. To keep the focusing of atomic hydrogen constant irrespective to its energy, we have developed a linear translator of the magnet system. The detection of atomic hydrogen was made by using a thermistor device. The operating condition and its limitation were studied. A preliminary measurement of reactive scattering of atomic hydrogen with a graphite surface was made at several temperatures.2. Measurement of the polarization of adsorbed atomic hydrogen To apply the beam-foil spectroscopy to the measurement of the poralization of adsorbed atoms, we have studied the ionization process of adsorbed atoms under irradiation of intense pulse laser. A method for the evaluation of the absolute intensity of ionized atoms was newly developed and was named "conductance modulation method".3. Measurement of ortho-para conversion of adsorbed hydrogen molecule. The rotational excitation of hydrogen was measured by using low-energy electron loss spectroscopy. The conversion rate was measured for several sufaces as follows: Ag(111), Xe/Ag(111), O^2/Ag(111).