EXPERIMENTAL GROUND-STATE G(J)-FACTOR OF BA+ IN A PENNING ION TRAP

We observed the Zeeman-splitting of the 6S1/2-6P1/2 resonance transition of Ba+-ions (493.4 nm) in a 6T magnetic field. The ions were stored in a Penning quadrupole trap. We polarized the ground state by optical pumping and in a microwave-optical double resonance experiment we measured the ground state Zeeman-splitting. From the resonance frequency and the cyclotron frequency of electrons stored in the same trap we derived the g-factor of the 6S1/2 state. The result is g(J)(6S1/2) = 2.002 490 6 (11), in reasonable agreement with recent calculations.