Potential Energy Surfaces for 1,2-Elimination

We can distinguish three general classifications of elimination reactions on the basis of the timing of these processes, and transition structures for each are 

Banthorpe, D. V. Elimination Reactions Elsevier Publishing Amsterdam, 1963. 

Saunders, W. H., Jr. Cockerill, A. F. Mechanisms of Elimination Reactions Wiley-Interscience New York, 1973. 

The three categories of 1,2-eliminations can be represented as paths on a More O Ferrall-Jencks diagram, a two-dimensional projection of a 

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