Journal of the Mass Spectrometry Society of Japan
Online ISSN : 1880-4225
Print ISSN : 1340-8097
ISSN-L : 1340-8097
46 巻, 6 号
選択された号の論文の4件中1~4を表示しています
総合論文
  • 竹内 孝江
    1998 年 46 巻 6 号 p. 477-482
    発行日: 1998年
    公開日: 2007/07/20
    ジャーナル フリー
    The fragmentation mechanisms of gaseous ions were studied experimentally and theoretically. In order to contribute to construction of fragmentation theory in mass spectra, the principle was examined using three separate approaches. Firstly, energy dependence on the fragmentation of molecular ions was investigated using the threshold electron-photoion coincidence (TEPICO) technique. Secondary, fragmentation mechanisms of molecular ions (n-butane, 1-propanol, n-propyl amine, and cycloglycylglycine cation radicals and a series of organosilicon cation radicals) in the low energy region were studied using ab initio molecular orbital (MO) methods. Finally, the dissociation (by hydrogen loss) of the first excited state (Ã2B1) of the formaldehyde cation as a function of its vibrational excitation was analyzed. Its mechanism involved an electronic predissociation by the ground X2B2 state in the tunneling regime. A statistical treatment for nonadiabatic interactions accounted for the low value of the rate constant as well as for a large isotope effect that persists over an energy interval of ca. 0.7 eV.
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