MICROWAVE SPECTROSCOPY OF HIGH-L RYDBERG STATES OF NEON

Sixteen fine-structure intervals separating n=10 neon Rydberg levels w ith L=5, 6, 7, and 8 were measured with the precision of about +/-00.2 MHz, using fast beam microwave-optical techniques. The measured fines tructure pattern is in good agreement with the predictions of an effec tive potential model, and this comparison leads to precise determinati ons of the quadrupole moment and dipole polarizabilities of the P-2(3/ 2) ground state of the Ne+ ion: Q=-0.20403(5)ea(0)(2), alpha(s)=1.3028 (13)a(0)(3), alpha(T)=-0.026(5)a(0)(3). The contributions of magnetic interactions to the Rydberg fine structure lead to a determination of the Ne+ ion's g value, g(J)=1.354(21). All of these core parameters pr ovide challenging tests of atomic structure calculations. The measurem ents also set a limit on the possible contributions to the fine struct ure due to a predicted geometric phase effect that is about an order o f magnitude smaller than expected.