Experimental isotope shifts of the 5 $^2S_{1/2}$ state and low-lying excited states of Rb

TL;DR

This paper reports precise measurements of isotope shifts in rubidium's ground and excited states, providing valuable data for spectroscopic analysis and atomic theory validation.

Contribution

It introduces the first accurate evaluation of isotope shifts for low-lying excited states of rubidium, including specific mass shift contributions.

Findings

Isotope shift of the 5$^2S_{1/2}$ ground state determined with high accuracy.

First evaluation of isotope shifts for low-lying excited states of rubidium.

Specific mass shift contributions identified in some cases.

Abstract

By combining a recent precise measurement of the ionization energy of $^{87}$Rb with previous measurements of electronic and hyperfine structure, an accurate value for the $^{85}\textrm{Rb}-^{87}\textrm{Rb}$ isotope shift of the 5$^2S_{1/2}$ ground state can be determined. In turn, comparison with additional spectroscopic data makes it possible for the first time to evaluate isotope shifts for the low-lying excited states, accurate in most cases to about 1 MHz. In a few cases, the specific mass shift contribution can be determined in addition to the total shift. This information is particularly useful for spectroscopic analysis of transitions to Rydberg states, and for tests of atomic theory.