Laser Spectroscopy of Thulium Isotopes Near the (N=82) Shell Closure: Nuclear Moment and Charge Radius of ${}^{152\mathrm{m}}\mathrm{Tm}$

Abstract

We report on resonance ionization laser spectroscopy measurements performed on both neutron-deficient and neutron-rich thulium ($\mathrm{Tm},Z=69$) isotopes. Isotope shifts were determined for three atomic ground-state transitions at wavelengths of $389.8\mathrm{nm}$, $388.4\mathrm{nm}$, and $388.8\mathrm{nm}$ in the isotopes ${}^{152\mathrm{m}}\mathrm{Tm}$, ${}^{153}\mathrm{Tm}$, ${}^{154\mathrm{m}}\mathrm{Tm}$, and ${}^{169}\mathrm{Tm}$. In addition, for the $389.8\mathrm{nm}$ transition, measurements were extended to the isotope ${}^{170}\mathrm{Tm}$, and the hyperfine structure was partially resolved for all five isotopes. For this transition, the isotope shift could be determined for one more isotope, ${}^{154\mathrm{m}}\mathrm{Tm}$. From the extracted hyperfine coupling constants, the nuclear magnetic dipole moment for ${}^{152\mathrm{m}}\mathrm{Tm}$ was determined for the first time, resulting in $\mu \left({}^{152\mathrm{m}}\mathrm{Tm}\right)=5.8(3){\mu }_{\mathrm{N}}$. Furthermore, the mean-square nuclear charge radius $\delta ⟨r^2{⟩}^{152\mathrm{m},169}=-1.86(25){\mathrm{fm}}^2$ for ${}^{152\mathrm{m}}\mathrm{Tm}$ was extracted from the measured isotope shifts.