Resonant Rydberg-atom — Rydbert-atom collisions

Abstract
The experimental investigation of the resonant collision process Nans+NansNanp+Na(n1)p which occurs when the levels are tuned with an electric field so that the ns level lies midway between the two p levels is described in detail. The observations are shown to be in good agreement with a long-range resonant dipole-dipole interaction.