Abstract

Beginning with Rice in 1929, many authors have considered a model of the so-called “quasi-continuum” in which a distinguished ground state is coupled to a band of N upper states, which are not coupled to one another (see Fig. ThDD3-1). These efforts are summarized nicely by Shore.¹ The (1,N) system allows many analytic results to be derived because it has a simple eigenvalue equation² and because it is susceptible to analysis using the Laplace transform.^3,4 In the special case (the Rice model) of evenly spaced sublevels of the upper band, Schrödinger’s equation can be transformed into a delay-differential equation^5,6 and hence exhibits recurrences in which the ground-state probability experiences quasi-periodic growth and decay (see Fig. ThDD3-2).

© 1984 Optical Society of America