Stability of Charged and Neutral Particles

Let us discuss again the primary fragmentation pathways of ion ABXY+  

It is known that in the vast majority of cases the activation energy E,. of the reverse reaction is very small or even negligible. Using Hammond s postulate [3], it is possible to assume that in the case of endothermic fragmentation the transition state will be much closer to the products than to the initial particle (Fig. 5.14). Thus, the stability of the products influences significantly the efficiency of fragmentation. It is important to consider stability of both products a neutral and a daughter ion. 

INTRODUCTION TO MASS SPECTRA INTERPRETATION ORGANIC CHEMISTRY 

The fragmentation may occur due to favorable delocalization of the unpaired electron in the neutral particle forming. Again the rules of classic organic chemistry 

The Loss of the Largest Alkyl Group. The preferential loss of the largest alkyl radical is the most important exception, as the abundance of the alternative analogous daughter ions decreases with the increase of their thermodynamic stability. 

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