0000000000358850
AUTHOR
K. H. Knöll
On the possible determination of hyperfine anomalies by trapped ion spectroscopy
Abstract Laser-microwave double-resonance techniques in radiofrequency (rf) traps and Penning traps represent a powerful tool to determine hyperfine structure splittings as well as nuclear g factors to high precision. While hyperfine structure constants have been determined in a number of cases below the 10 −10 level of precision, electronic g factors have been measured to 10 −7 and there are good prospects of obtaining similar accuracy for g l . Moreover sensitive techniques have been developed for injection of ions from outside the trap. This opens the possibility to determine hyperfine anomalies at least to the 1% level of precision for chains of unstable isotopes.
Hyperfine structure andg-factor measurements in ion traps
We report about measurements on ground-state hyperfine splitting constants of stable Eu+ isotopes in radio frequency ion traps and experiments on the electronicg-factor of Ba+ in a Penning trap. From the precision of both measurements, which ranges between 3·10−6 and 5·10−7, we conclude that precise determination of the differential Bohr-Weisskopf effect in chains of isotopes will be possible in the near future.
Experimental ground stateg 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 theg-factor of the 6S1/2 state. The result isgJ(6S1/2)=2.002 490 6(11), in reasonable agreement with recent calculations.
Ground- and excited stateg-factors of Ba+
We observed the Zeeman-splitting of the 6S 1/2-6P 1/2 resonance transition of Ba+ ions (493.4 nm) in a 6 T magnetic field. The ions were stored in a Penning quadrupole trap. From the splitting and the simultaneously measured cyclotron frequency of stored electrons we derived theg-factors of the 6S 1/2 and 6P 1/2 states. The results areg(6S 1/2)=2.00267(20) andg(6P 1/2)=0.66634(22).
ExperimentalgJfactor in the metastable 5D3/2level ofBa+
The Zeeman splitting of the metastable 5${\mathit{D}}_{3/2}$ level of $^{138}\mathrm{Ba}^{+}$ in a magnetic field of 6 T has been measured in a laser-microwave double resonance experiment in a Penning ion trap. The magnetic field at the ion's position is determined by the cyclotron frequency of electrons stored in the same trap. From the ratio of both transition frequencies we obtain a ${\mathit{g}}_{\mathit{J}}$ value of 0.799 327 8(3). As a by-product, we confirmed earlier measurements on the 6${\mathit{S}}_{1/2}$ ground-state ${\mathit{g}}_{\mathit{J}}$ factor to 2.002 492 2(10). The precision in both experiments is sufficient to test relativistic many-body calculations. \textcopyright{}…