How Does a Reaction Path Branching Take Place ? 
A Classification of Bifurcation Events

by  Wolfgang Quapp

Mathematisches Institut, Universit"at Leipzig,
Augustus-Platz, D-04109 Leipzig,  Germany 

 quapp@rz.uni-leipzig.de

 Key words: Reaction path bifurcation; Projected gradient; 
            Valley-ridge-inflection point;
             Pitchfork bifurcation; Classification of VRIs

submitted for  the special edition of
Journal of Molecular Structure for Brenda and Manfred Winnewisser

 Abstract

Valley-ridge-inflection points (VRI) of a potential energy surface
(PES) may have a strong relation to bifurcations of chemical 
reaction pathways.
We explain how a reaction path has to be defined to describe 
the bifurcation of a ``valley" of the PES.
We propose a classification of different VRI events: valley bifurcation, 
ridge bifurcation, and the mixed case in between. 
Chemical implications of the different cases are discussed.