A contribution to a theory of mechanochemical pathways by means of Newton trajectories

The reaction path is a central subject in theoretical chemistry. It is a pathway imagined on the potential energy surface (PES). It provides a one-dimensional description of a chemical reaction in an N-dimensional configuration space. Additionally, one can apply mechanical stress in a defined direction to the molecule and generate an effective PES. Changes for minima and saddle points by the stress are described by Newton trajectories on the original PES. The barrier of a reaction fully breaks down for the maximal value of the norm of the gradient of the PES along a pulling Newton trajectory. This point is named barrier breakdown point. We discuss topologically different, two-dimensional examples for this model to understand and classify the mechanochemistry of molecules.