Polarizability ofKr6+from high-LKr5+fine-structure measurements

Abstract

The transition between $n=55$ and $n=109$ Rydberg levels of ${\mathrm{Kr}}^{5+}$ has been studied at high resolution using the resonant excitation stark ionization spectroscopy method. Resolved excitation of $L=6$, 7, 8, and 9 levels in $n=55$ lead to a determination of the fine-structure energies of these levels. Interpreted with the long-range polarization model, this leads to a measurement of the dipole polarizabilities of Zn-like ${\mathrm{Kr}}^{6+}$, ${\ensuremath{\alpha}}_{d}=2.69(4){a}_{0}^{3}$. Obtaining a value of the quadrupole polarizability from the data will require additional theoretical input. Factors contributing to the signal and noise levels in measurements of this type are discussed.