where [⌫ R ](t) denotes the time-dependent population of the product well state |⌫ R i under the steady-state approximation, and [⌫ L (0)] denotes the initial population of |⌫ L i. Eq. 42 indicates that under the steady-state limit, the reaction rate constant is described by the growth of the |⌫ R i population, with the apparent rate constant k 1 .