Metastable ions following charge exchange

If metastable ions are observed in charge exchange experiments, both the lifetime and the internal energy of the reactant are defined as in the analogous PIPECO experiment. The energy at which the intensities of the reactant and fragment ion in the breakdown curve become comparable may be used as a guide as to where to look for metastable ions, 

Studies specifically concerned with metastable ions from charge exchange are not numerous. Cis- and trans-2-butene have been studied and metastable peaks reported for mjz 5Q mjz 41, mjz 55mjz 39, mjz 55 m/z 29 and mjz 41 - m/z 39 [811]. 

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Since, according to Turner and May, N2 has, among others, the following IP s 16.73, 16.96, and 18.78 eV, charge exchange with in the metastable states can easily take place, as their RE s are 16.67, 16.94, and 18.64 eV. A study of the attenuation as a function of pressure enabled Turner et al to determine the fraction of excited states in O when produced from O2 as about 30%, in good agreement with the value of about 40% obtained at Stockholm for 0 ions produced from CO2. This method has also been used for and (see Table I). 

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