Dissociative Ionization Dynamics of Molecules via Excited state by Optical Forbidden Transitions

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First of all, the energy selector and analyzer for electrons had been installed in our Time of Flight Mass Spectrometer. The impact energy of the spectrometer can be varied from 100 to 500 eV, and the typically energy resolution is about 80 meV (full width at half maximum=FWHM). Secondly, I had obtained the electron energy-loss spectra for nitric oxide (NO), and the generalized oscillator strengths for valence excitation 3sσ(v'=0-3) of NO had been determined in the momentum transfer range K^2=0-0.8. For this experiments, I had also used the electron energy-loss spectrometer at the Institute for Laser Science in the University of Electro-Communications.On the other hand, the kinetic energy measurements of fragment ions had been carried out to obtain the information of the dissociative ionization dynamics of molecules, methane, hydrogen, water, and ammonia by electron impact. In particular, the kinetic energy distributions for proton by the fragmentation of methane had been determined. A … More time-of-flight (TOF) mass spectrometer with a pulsed electron gun had used for these experiments. (Not coincidence). I can distinguish between thermal and energetic ions on a TOF spectrum by using the time-lag defined by the time between the ionization of the ions and application of the extracting pulse. During this time-lag, since the energetic ions are dispersed from the ionization region, I can't detect the energetic ions except ones that move in the direction of the detector. However, since the thermal ions move little, all of thermal ions can be detected. Then the kinetic energy distributions of fragment ions are calculated with considering the collection efficiency of ions. These results have been already published as the paper (see next page), and I had given two invited talks.Finally, I had installed the quadrupole mass spectrometer in our apparatus. For this modification, the coincidence rate should be better than that by TOF spectrometer. At present, I adjust the apparatus, and I hope that the new coincidence results will be obtained in the near future. Less