Computer simulation of the vibrational spectrum of a simple system with ultrafast chemical reaction

A very simple model is constructed consisting of a rigid cavity containing a diatomic molecule and monoatomic one. The force constant of the diatomic molecule depends on its distance from the monoatomic one and an energy barrier separates the two molecules. Spectra are obtained for different barrier heights and at different temperatures. The effects of exchange broadening are strikingly demonstrated, the spectra may be fit well by the Bloch equations line shape and the activation energies derived correspond quite well to the barrier heights used in the model.