MICROWAVE FORCED AUTOIONIZATION OF NA(2) RYDBERG STATES

We have examined the ionization of Na2 Rydberg states of principal quantum number n =11 - 16 converging to rotational-vibrational, v =3-6 and R < 10, states of Na2+ by 8-GHz microwave fields. Rydberg states lying below the lowest, v =0, R =0 (v and R are the vibrational and rotational quantum numbers of the molecular ion), ion limit of Na2+ are observed to ionize at approximately E =1/3n(0)5, where no is the effective quantum number relative to the v =R =0 limit. The agreement with this dependence is not nearly as good as in an atom, and the possible reasons for the deviations are discussed.