Precision measurement of Cs($nF_J$) quantum defects and calculations of scalar and tensor polarizabilities of the $nS_{1/2}$, $nP_J$ ,$nD_J$ , and $nF_J$ series

TL;DR

This study provides precise measurements of cesium Rydberg states, determines quantum defects, and calculates scalar and tensor polarizabilities, enhancing understanding of cesium's atomic properties for various applications.

Contribution

The paper extends previous work to F states, providing new absolute frequency measurements, quantum defect determinations, and polarizability calculations for cesium Rydberg series.

Findings

Quantum defects for $nF_{5/2}$ and $nF_{7/2}$ series determined.

Ionization potentials agree with previous S and D series measurements.

Calculated scalar and tensor polarizabilities for multiple series with improved accuracy.

Abstract

In this paper, we extend our recent work on cesium S and D states [Phys. Rev. Lett. 133, 233005 (2024)] to the F states. We present absolute frequency measurements of the $|6S_{1/2}, F = 3\rangle \rightarrow nF_{5/2,7/2}(n = 28-68)$ Rydberg series to measure the spectrum of $^{133}$Cs. Atomic spectra are obtained using a three-photon excitation scheme referenced to an optical frequency comb in a sample of ultracold $^{133}$Cs. By globally fitting the absolute-frequency measurements to the modified Ritz formula, we determine the quantum defects of the $nF_{5/2}$ and $nF_{7/2}$ series. The ionization potential extracted for both series from the modified Ritz formula agrees with our measurements based on the S and D series. Fine-structure intervals are calculated and parameterized. The wave functions computed for the energies from the quantum defects are used to calculate transition dipole moments. We compare the reduced electric-dipole matrix elements with available benchmarks and find agreement within the precision of those works. The scalar and tensor polarizabilities of the $nS_{1/2}$, $nP_J$ , $nD_J$ and $nF_J$ series are calculated based on the now more accurate set of wave functions. Moreover, we report the polarizability as a series in powers of the effective principal quantum number and find the main coefficients of the expansion. The results will be useful for calculating properties of $^{133}$Cs such as collision and decay rates, polarizabilities, and magic wavelengths.