Polarizability of Rn-like Th4+ from spectroscopy of high-L Rydberg levels of Th3+

Abstract

Binding energies of high-L Rydberg levels of Th3+ were measured using the resonant excitation Stark ionization spectroscopy technique. Analysis of the data with the long-range polarization model leads to determination of dipole and quadrupole polarizabilities of the free Th4+ ion, αd = 7.61(6) a.u., αQ = 47(11) a.u.