Time-dependent effective rates for molecular processes

The concept of time-dependent effective rates for molecular processes such as luminescence, introduced in our earlier work, is developed further by obtaining two new results. One is the explicit evaluation of those rates for four initial conditions corresponding to experimentally relevant methods of excitation of the molecule. The other is a proof that the limiting values of those rates for long times or for infinitely fast relaxation are independent of the initial condition. The latter result extends the validity of the rate depression effect (whereby the long time limit of the effective rate is different from its thermalized value) to arbitrary initial conditions.On leave of absence from the Department of Physics and Astronomy, University of Rochester, Rochester, New York 14627 (permanent address)