Optical spectroscopy of high-LRydberg states of nickel

Abstract

Binding energies of 23 Rydberg fine-structure levels of Ni with n $=$ 9 and $L\ensuremath{\geqslant}5$ were measured using resonant excitation Stark ionization spectroscopy. From this spectrum, the quadrupole moment and the scalar and tensor dipole polarizability of the ${}^{2}{D}_{5/2}$ ground state of Ni${}^{+}$ were determined to be $Q=\ensuremath{-}0.474(2)$, ${\ensuremath{\alpha}}_{d,0}=7.92(6)$, and ${\ensuremath{\alpha}}_{d,2}=1.15(14)$ a.u. The electric hexadecapole moment was determined to be $\ensuremath{-}0.33(21)$ a.u.