A model for the direct introduction of mechanical energy into electronic degrees-of-freedom of molecules in crystals is discussed. This model is related to the hypothesis of HOMO-LUMO gap closure for detonation initiation. However, it is demonstrated that complete gap closure is not required for chemical processes to occur with the amount of closure related to chemical hardness. A new area of mechanochemistry can be developed where novel chemistry can be found. It is proposed that the term "mechanochemistry" be limited only to those chemical processes that are not driven by the thermalization of the mechanical energy.