DETERMINATION OF BIFURCATIONS FROM RECURRENCE PEAKS OF ELECTRONIC WAVEPACKETS IN AN ELECTRIC-FIELD

A new and simple way to determine the bifurcations of electron orbits in an electric field is presented. From the quantum-mechanical wavepac ket motion the classical energies at which new orbits bifurcate from t he uphill and downhill orbits are obtained. This is an application of the inverse correspondence principle, since the discrete quantum spect rum is used to calculate classical features of the system. It is shown that at every bifurcation the periods of wavepacket motion in the rad ial and angular-momentum coordinate are commensurable. Therefore, all recurrences seen in electronic wavepacket experiments with Rydberg ato ms in an electric field are the direct result of these bifurcations. T o illustrate our point, experimental spectra before and after the bifu rcation of the so-called 2/3 orbit are presented.