Sequential (secondary) simple cleavages may also occur. For example, the fragment AB (produced by reaction (1) in Section 6.3.1) may continue to decompose:
Notice that there are two ways to form an ion at the nominal mass
of A (reaction (3) in one step and sequential reactions (1) followed
by (7)), and two ways to form an ion at the mass of B. We have proposed
two mechanisms for the formation of both A and B ions: a one-step
mechanism and a two-step mechanism. The two mechanisms will probably
have different kinetics; one or both pathways to A, for example, may
The multiplicity of A formed by the two different mechanisms is different. The A ion formed by reaction (3) is most likely in a singlet state, whereas formation of the A ion formed by reaction (1) then reaction (7) is most likely in a doublet state. The structures of these two product ions will therefore possibly be different, though they lie at the same mass.