Nuclear moments of the low abundant natural isotope 176Lu and hyperfine anomalies in the lutetium isotopes

The atomic beam magnetic resonance method combined with laser-induced state- and isotopeselective detection of metastable atoms has been used to investigate the hyperfine structure of the ²D ground multiplet in ¹⁷⁵Lu and ¹⁷⁶Lu. The analysis of the data yields not only accurate values for the hyperfine interaction constants, the nuclear magnetic dipole moment of ¹⁷⁵Lu, and the electronic g_J, factors, but also the first directly measured value of the nuclear magnetic dipole moment of the low abundant isotope ${}^{176}\text{Lu}\text{: μ}{}_{\mathrm{I}}\text{(}{}^{176}\text{Lu) = 3.1692 (45)μ}{}_{\mathrm{<mtext>N</mtext>}}$ (corrected for diamagnetic shielding). The spectroscopic quadrupole moment of ¹⁷⁶Lu was calculated from the ratio of the B-factors and the quadrupole moment of ${}^{175}\text{Lu}\text{: Q}{}_{\mathrm{<mtext>s</mtext>}}\text{(}{}^{176}\text{Lu}\text{) = 4.92 (3)}\text{b}$. Moreover, the magnetic hyperfine anomalies for the isotopic chain ^{175,176,176m,177}Lu were determined. A quadrupole hyperfine anomaly between ¹⁷⁵Lu and ¹⁷⁶Lu was not found when comparing the ratio of the B-factors in the states ${}^2\text{D}{}_{\mathrm{<mtext>3</mtext><mtext>2</mtext>}}\text{and}{}^2\text{D}{}_{\mathrm{<mtext>5</mtext><mtext>2</mtext>}}$. From a comparison of the quadrupole moment of ¹⁷⁵Lu obtained from the hyperfine structure data and the quadrupole moment measured in muonic lutetium atoms semi-empirical Sternheimer shielding factors could be estimated.