Reaction Initiation at Radical or Charge Sites

The most favored radical and charge sites in the molecular ion are assumed to arise from loss of the molecule s electron of lowest ionization energy (IE, Table A.3). Relative energy requirements are similar to those for the electronic transitions affecting ultraviolet spectra favorability for ionization generally is on the order of a- n- n-electrons. 

The symbol at the end of the molecule signifies an odd-electron ion without designating the radical site. Use of either or within the molecule, as in CHj CHj, implies localization of the radical or the charge. 

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