The Implementation of Ion-Cyclotron-Resonance Mass Spectrometer

为了研究在相变现象和薄膜制备过程中起重要作用的分子和原子团簇，研制了傅里叶变换离子回旋共振(FT-ICR)光谱仪。作为该装置的演示，用电弧放电法获得了富勒烯混合物的质谱图。富勒烯样品在ICR池附近蒸发和电离，生成的离子被捕获在池中。在扫频激励后，离子回旋运动产生的感应电流通过差动放大器由数字示波器检测。将信号传输到计算机后，进行傅立叶变换，得到质谱图。结果表明，C&lt；60&gt；和C&lt；70&gt；峰的各向同性分布与利用天然丰度^&lt；13&gt；C计算的分布符合得很好。结果表明，用该装置可以很容易地在1000amu范围内获得至少1amu的质量分辨率。利用飞行时间质谱仪对激光汽化超音速膨胀团簇束源进行了独立测试。在不久的将来，将在FT-ICR装置上安装团簇源，以进行进一步的化学反应和团簇激光探测实验。另一方面，对最著名的富勒烯簇合物进行了分子动力学模拟研究。通过理论研究，探讨了富勒烯的形成机理。使用FT-ICR装置的实验对应物将在未来进行。

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.