Polarizabilities of Rn-like Th4+from rf spectroscopy of Th3+Rydberg levels

Abstract

High-resolution studies of the fine-structure pattern in high-L n = 37 levels of Th 3+ have been carried out using radio-frequency (rf) spectroscopy detected with resonant excitation Stark ionization spectroscopy (RESIS). Intervals separating L = 9 to L = 15 levels have been measured, and the results analyzed with the long-range effective potential model. The dipole polarizability of Th 4+ is determined to be α D = 7.720(7) a.u. The quadrupole polarizability is found to be 21.5(3.9) a.u. Both measurements represent significant tests of a priori theoretical descriptions of this highly relativistic ion.

Measurements of dipole and quadrupole polarizabilities of Rn-like Th4+

“…3 in Ref. [1], and a corresponding improvement in the precision of the primary fit parameters. A second improvement in the data pattern was improved precision of the highest L intervals, the three-photon L = 12 to L = 15 interval and the two-photon L = 12 to L = 14 interval.…”

“…Measurements of the binding energy differences between n = 37 Rydberg levels of Th 3+ with 9 L 15 were recently reported [1], and used to infer the dipole and quadrupole polarizabilities of Th 4+ . We report here an extension and improvement of that study that leads to improved precision in the inferred polarizabilities.…”

“…In addition to these improvements in the data pattern, theoretical calculations of the two parameters γ D and δ, discussed in Ref. [1], were received [2] and incorporated in the analysis, reducing uncertainty from possible higher-order contributions to the fine structure pattern.…”

Polarizabilities ofSi2+: A benchmark test of theory and experiment

“…In such cases, the polarization interaction provides the dominant contribution to the energy shift. This effect is utilized in resonant excitation Stark ionization spectroscopy (RESIS) [19][20][21][22][23][24][25][26][27][28] [26], and Rnlike Th 3+ [27]. Quadrupole polarizabilities and transition matrix elements have also been determined for some of these systems.…”

Calculation of quadrupole polarizabilities with combined configuration interaction and coupled-cluster method

“…This approach has been used to determine the ground state quadrupole polarizabilities of Mg + [10], Ba + [11,12], and Th 4+ [13,14]. The lowest electric-quadrupole matrix elements involving the ground state, which generally give the dominant contribution to α 2 have been determined using the RESIS method for the 6s − 5d j transitions in Ba + [15] and 5f 5/2 − 6d j transitions in Th 3+ [16].…”