A scaled hypersphere search method for the topography of reaction pathways on the potential energy surface

Global reaction route mapping, a fully-automated search for all important reaction pathways relevant to a given purpose, on the basis of quantum chemical calculations enables systematic elucidation of complex chemical reaction mechanisms. Scaled hypersphere search — an algorithm for finding pathways to transition states or dissociation channels from equilibrium structures on the potential energy surface is implemented. The pathways around an equilibrium structures can be discovered at minima on the scaled hypersphere which would have a constant energy when the potentials are harmonic.

In this work scaled hypersphere search algorithm was implemented and was used to analyze the potential energy surfaces of water, eten and propene molecules. Basic geometry optimization algorithms were implemented and were used inside scaled hypersphere search algorithm and to re-optimize received approximate transition structures to corresponding true transition structures.