TIME-RESOLVED CONFIGURATION-INTERACTION

Using the optical Ramsey method we have observed the configuration int eraction in Pa drive atoms back and forth between the doubly excited 5 d7d state and the degenerate 6snd Rydberg states. Our observations on be understood qualitatively as autoionization of the initially excited 5d7d state into the Rydberg states, followed by capture of the Rydber g electron by the Ba+ ion a Kepler time later. After a time delay, the whole process repeats. A quantum defect theory description provides a quantitative picture and clarifies the connection to resonance scatte ring.