INTRA-SHELL RF-RESONANCES IN Li RYDBERG ATOMS

A. WAHEED; D. FREGENAL; O. FRETTE; B.T. HJERTAKER; E. HORSDAL

Salamanca

Conferencia; 10th European Conference on Atoms Molecules and Photons; 2010

European Physical Society

Intra-shell transitions in Rydberg atoms with a non-hydrogenic core were studied. Transitions from initial coherent elliptic states (CES) were driven by short pulses of linearly polarized, time harmonic electric fields in the radio frequency (RF) regime (20-130MHz). The CES were formed by selective laser excitation of the n=25 Stark state of highest energy in a strong electric field followed by adiabatic transformation of the Stark state when the electric field was decreasing slowly in the presence of a constant magnetic field perpendicular to the electric field. The final electric field (0,E,0) and the constant magnetic field (0,0,B) defined the eccentricity, e, of the initial CES and lifted the hydrogenic degeneracy of the n-shell. Sharp N-photon resonances with N=1-4 were seen at low e and weak time-harmonic fields, but at higher e and stronger RF fields the resonances broadened and new structures emerged. These can not immediately be tied to multiphoton resonances. We suspect that the underlying classical dynamics is chaotic due to core-scattering.