Dish-topped metastable peaks: the variation of their shapes as a function of the degree of angular collimation of the parent ion beam and the field-free region in which the fragmentations occur

A method for calculating the shapes of peaks resulting from fragmentations of metastable ions in a mass spectrometer. II. Peak shapes arising from a distribution of kinetic energy releases: determination of distribution function

Following the calculations described in the preceding paper (part I), which determine the MIKE peak shape arising from a discrete kinetic energy release, a method is presented for extending the calculations for the determination of the kinetic energy release distribution, n (T), from any experimental peak shape. This new approach has the advantage, compared to previous work, that the distribution can be obtained directly and does not involve any trial and error methods. It applies equally well where discrimination occurs against some of the product ions having components of velocity parallel to the length of the instrument slits. A variety of peak shapes have been investigated and several examples are given of the energy release distribution for various ionic reactions. Charge separation reactions of doubly-charged ions have been examined and in one case, the reaction 91 2+ -> 52 + in toluene, the energy release function exhibits fine structure, which has not previously been observed.