Development of Time-of-Flight Fourier Transform Mass Spectrometer and its Application to a Novel Surface Analysis Technique

我们基于一种新的原理构建了一台离子光谱仪，并研究了该光谱仪在电子刺激脱附(ESD)实验中的应用。该光谱仪被称为飞行时间傅里叶变换离子光谱仪(TOFFTIS)，具有极高的探测效率，实现了角分辨电子刺激解吸离子光谱。计算机模拟结果表明，采用0.1m飞行管的TOFFTIS可以分析约10 eV的轻离子能量分布。然而，计算机模拟的结果表明，飞行管小于1米的TOFFTIS由于质量分辨率差而不能用作质谱计。因此，我们只是在检验TOFFTIS作为ESD离子能量分析器的性能。通过同时测量电子轰击下从固体表面解吸出的离子的角度分布和能量分布，可以确定吸附在固体表面的化学物种的取向和成键状态。我们还通过高分辨率电子能量损失谱(HREELS)记录被吸附物种的振动光谱和通过低能电子衍射(LEED)检查吸附物种的有序结构来研究吸附物种在固体表面的取向和成键状态。我们考察了(一氧化碳+氨)、(一氧化碳+乙二烯)和(一氧化碳+甲胺)在Ru(001)表面的共吸附体系。我们观察到共吸附时有序结构的形成，发现一氧化碳在氨、乙炔和甲胺的解离过程中起着关键作用。我们讨论了分子间相互作用的性质以及通过添加共吸附物质作为控制剂选择性激活化学键的可能性。

We have constructed an ion spectrometer based on a novel principle and studied on the application of this spectrometer to electron stimulated desorption (ESD) experiment. The spectrometer is called TOFFTIS (time-of-flight Fourier transform ion spectrometer) and has an extremely high detection efficiency, which realizes angle-resolved electron-stimulated-desorption ion spectroscopy. The results of computer simulation indicated that TOFFTIS with a 0.1-m flight tube can analyze energy distribution of light ions of about 10 eV. The results of computer simulation indicated, however, a TOFFTIS with sub-1-m flight tube cannot be used as a mass spectrometer because of bad mass resolution. We, therefore, are examining the performance of TOFFTIS only as a ion energy analyzer for ESD. It is expected that simultaneous measurement of both angular and energy distribution of ions desorbed from solid surfaces by electron impact allow the determination of orientation and bonding states of chemical species adsorbed on solid surfaces.We also carried out studies on orientation and bonding states of adsorbed species on solid surfaces by recording vibrational spectra of adsorbed species by high-resolution electron energy loss spectroscopy (HREELS) and by examining ordered structures of adsorbates by low-energy electron diffraction (LEED). We examined co-adsorption systems of (carbon monoxide+ammonia), (carbon monoxide+acetilene), and (carbon monoxide+methylamine) on the ruthenium (001) surface. We observed the formation of ordered structures upon co-adsorption and found that carbon monoxide plays a key role in the dissociation of ammonia, acetylene, and methylamine. We discussed the nature of intermolecular interaction and the possibility of the selective activation of chemical bonds by adding co-adsorbates as controling agents.