Abstract
The solution of the Schrödinger time-dependent equation is discussed in a form suitable for chemical kinetics. The evolution of the system is considered with respect to the simultaneous evolution of independent events and the sequence evolution of events. The lifetime is defined as the average duration of an event. It is shown to be the inverse of the rate constant for the activated states. The distinction between unimolecular and bimolecular reactions is discussed and the realization of genuine termolecular processes is considered.