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

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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.