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Ion cyclotron resonance is a phenomenon related to the movement of ions in a magnetic field. It is used for accelerating ions in a cyclotron, and for measuring the masses of an ionized analyte in mass spectrometry, particularly with Fourier transform ion cyclotron resonance mass spectrometers. It can also be used to follow the kinetics of chemical reactions in a dilute gas mixture, provided these involve charged species. ==Definition of the resonant frequency== An ion in a static and uniform magnetic field will move in a circle due to the Lorentz force. The angular frequency (''ω = 2π f'') of this ''cyclotron motion'' for a given magnetic field strength ''B'' is given by : where ''z'' is the number of positive or negative charges of the ion, ''e'' is the elementary charge and ''m'' is the mass of the ion.〔In SI units, the elementary charge ''e'' has the value 1.602×10−19 C, the mass of the ion ''m'' is often given in atomic mass unit or dalton 1 u = 1 Da ≈ 1.660538782(83) × 10−27 kg, the magnetic field ''B'' is measured in teslas, and the angular frequency ω is measured in radians per second.〕 An electric excitation signal having a frequency ''f'' will therefore resonate with ions having a mass-to-charge ratio ''m/z'' given by : The circular motion may be superimposed with a uniform axial motion, resulting in a helix, or with a uniform motion perpendicular to the field, e.g., in the presence of an electrical or gravitational field, resulting in a cycloid. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「ion cyclotron resonance」の詳細全文を読む スポンサード リンク
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