Landau-Zener Transitions in Frozen Pairs of Rydberg Atoms

We have induced adiabatic transitions in pairs of frozen Rydberg sodium atoms of a supersonic beam. The diatomic ns + ns -> np + (n - 1)p transition takes place in a time-dependent electric field and originates from the adiabatic change of the internal state of the pair induced by the dipole-dipole interaction. This is experimentally achieved by sweeping an electric field across the energy degeneracy ns ns - np(n -1)p. Our results fully agree with a two-level Landau-Zener model in the diatom system.