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The half-width and half-height for power absorption in the ICR spectrometer is shown to depend upon the time during which an ion absorbs power in the detection region of the instrument. In the case of negative ions, it is shown that autoionization can limit resolution, and conversely that the observed resolution for a given negative ion can be used to determine autoionization lifetimes. The SF6-ion is observed in the ICR spectrometer, and a lifetime of ~500 JLsec is calculated for this ion. The C,F 8-ion is observed, and a lifetime of ~200 JLsec is calculated for that ion. The lifetimes are discussed with respect to other measured and calculated values, which show a wide variation, and it is suggested that the autoionization lifetimes may be strongly dependent on the energy of the impacting electrons. In this study, both ions are shown to be produced by electrons which are trapped in the ICR cell as opposed to being produced by beam electrons.

A branching chain mechanism is observed in the methanol ion-molecule system which involves complex formation and collisional stabilization of complex ions. A protonated methanol ion CH3OH2+ is the main product of the reactions of primary ions present. Collisions of this ion with methanol lead to complex ions (CH3OH)"H + at high pressure. At lower pressure, in the absence of collisional stabilization, a protonated dimethyl ether ion (CH3)2OH+ is produced. The structure of the (CH3)2OH+ ion was verified, and the effects of mode of formation and internal excitation on ionic reactivity were observed. The lifetime of the (CH3OH)2H+ and (CH3)2OH+ ions were estimated to be 2 X KM and 1 X KM sec, respectively. A comparison of ion cyclotron resonance with sector mass spectrometry is made, and the unusual and useful features of cyclotron resonance are discussed. Among the important advantages of ion cyclotron resonance spectrometry are long ion path length and ion lifetimes, and the ease with which path lengths and residence times can be varied. Also important is the ability to study reaction sequences of high-order ions using double-resonance techniques.A program has been developed in this laboratory using ion cyclotron resonance techniques to study gasphase ion-molecule reactions. This paper is concerned with the properties of ion cyclotron resonance (icr) as they pertain to such reactions in methanol. Previous reports of ion-molecule reactions in methanol have appeared in the literature and provide an excellent basis for comparing icr with other techniques used in the study of ion-molecule chemistry. Since this is the first report of our work in this field, a discussion of equipment and experimental techniques is included.