Isomeric ions, reactive probing potential energy surfaces

REACTIVE PROBING OF THE POTENTIAL ENERGY SURFAC ISOMERIC IONS... 

In the following sections, studies of isomeric ions are reported in which the ions are reactively probed. Where calculations are available, information on potential energy surfaces is given. This is usually the structure of the stable isomeric forms and transition states and their relative energies thus only points on the potential surface are known. The detailed form of the potential surface is almost never available nor is the connectivity between the various states usually established theoretically (chemical intuition is often used to connect the states). Pertinent experimental data on CID and metastable ions, isomers produced in binary reactions, and potential surfaces probed by binary reactions (with the excited isomeric ion as the reaction intermediate) are also given. 

When isomeric ions were produced by ternary association in the flow tube, thus allowing the potential surface to be accessed, the chemistry was more complicated. The gas with which the ions associated was added upstream and sufficient time was allowed for the association reaction to proceed before the reactant gas was added. When the associated ions are initially produced, they will be stable against dissociation if ternary collisions with the He remove sufficient energy to take them below the dissociation limits. However, they will still be internally excited and this excitation needs to be removed before the reactivity is probed. Again, the bulk of the evidence suggests that this de-excitation has occurred before the reactant gas is added. In a few cases there is some indication of residual excitation (see Section... 

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