The Implementation of Ion-Cyclotron-Resonance Mass Spectrometer

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In order to study molecular and atomic clusters which play the very important role in phase change phenomena and thin film production process, a Fourier Transform Ion Cyclotron Resonance (FT-ICR) spectrometer was implemented. As the demonstration of this apparatus, a mass spectrum of the fullerene mixture by the arc-discharge method was obtained. The fullerene sample was vaporized and ionized near the ICR cell and the resultant ions were trapped in the cell. After the excitation by the frequency sweep, the induced current from the ion-cyclotron motion was detected by a digital oscilloscope via a differential amplifier. After transferring the signal to the computer, the Fourier transformation was employed to obtain the mass spectrum. As a result, the isotropic distributions appeared in C_<60> and C_<70> peaks were in good agreement with the calculated distributions using the natural abundance of ^<13>C.This results demonstrated that at least 1 amu mass resolution in the range of 1000 amu was easily achieved with this apparatus. The laser-vaporization supersonic-expansion cluster beam source was independently tested with a TOF mass spectrometer. The installation of the cluster source to the FT-ICR apparatus for the further experiments of chemical reaction and laser probe of clusters will be done in the near future. On the other hand, for the most famous cluster fullerene was studied through a molecular dynamics simulations. A formation mechanism of the fullerene was discussed by the theoretical studies. The experimental counterpart using the FT-ICR apparatus will be done in the future.