ELECTRIC FIELD IONIZATION OF SODIUM RYDBERG ATOMS

The outer electron of a Rydberg atom is so weakly bound to the atomic core that a relatively small electric field may cause the electron to be stripped from the atom. The field strength at which this ionization happens is strongly dependent on the state of the Rydberg atom. Pulsed electric field ionization serves, therefore, not only as a means by which a Rydberg atom may be efficiently detected, but also a means by which the state of the Rydberg atom may be analyzed. The first observation of predominantly diabatic passage to field ionization of a non-hydrogenic Rydberg atom has resulted in an improved understanding of the adiabatic and diabatic ionization processes. The magnitudes of the various field ionization features have been measured and found to agree with theory, and by detailed analysis, it is now possible to label the various field ionization signal features with the appropriate (VBAR)m(,l)(VBAR) quantum numbers. A much better understanding of the laser excitation process, the Rydberg state production, and the response of the excited state to an increasing electric field has enabled measurement of some Rydberg fine-structure intervals, through observation of field ionization quantum beats