OSCILLATIONS IN THE REFLECTIVITY OF A DIFFUSE POLYMER LAYER - AN ANALOGY WITH THE RAMSAUER TOWNSEND EFFECT

The reflectivity of a diffuse, finite layer of adsorbed polymers is ex amined. If the bulk solution is semi-dilute, the screening structure g enerates oscillations in the reflectivity function in the vicinity of total reflexion. The deviation with respect to the Fresnel law increas es with the depth of the layer. In the limit of infinite depth the ref lectivity function displays the discontinuity first predicted by Schac k (Thesis, Munich 1986) and first observed by Guiselin (Europhys. Lett . 17 (1992) 57). In our approach, we make use of earlier results obtai ned by Morse and Feshbach in their interpretation of the Ramsauer-Town send effect of slow electrons scattered by heavy atoms.