Energy Deposition and Rate Functions

Note that the shaded areas of the P(E) curve represent the initial abundances of AD and AB . Those ions formed with sufficient internal energy will decompose further the abundances of the resulting product ions (and of the undissociated AD and AB ) will depend in turn on the P(E) and k(E) functions of AD and AB+. 

These offsetting enthalpy and entropy effects in general lead to a substantial number of competing primary reactions as well as the consecutive secondary and further reactions thus the mass spectrum of a larger molecule can have hundreds of peaks. The competitive nature of these reactions can mean that relatively small changes in molecular structure result in large differences in peak abundances. For this reason, in interpreting an unknown spectrum it is helpful to study the spectra of closely related compounds. 

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