Isotope Shift Measurements of Stable and Short-Lived Lithium Isotopes for Nuclear Charge Radii Determination

TL;DR

This study combines precise isotope shift measurements and advanced atomic calculations to determine nuclear charge radii of lithium isotopes, including short-lived halo nuclei, revealing detailed nuclear structure information.

Contribution

It introduces a novel laser spectroscopic method that is highly sensitive, fast, and accurate for measuring tiny field shifts in lithium isotopes, even with very low production rates.

Findings

Determined nuclear charge radii for all lithium isotopes including Li-11.

Developed a new laser spectroscopy technique suitable for short-lived isotopes.

Provided improved theoretical and experimental values for isotope shifts.

Abstract

Changes in the mean-square nuclear charge radii along the lithium isotopic chain were determined using a combination of precise isotope shift measurements and theoretical atomic structure calculations. Nuclear charge radii of light elements are of high interest due to the appearance of the nuclear halo phenomenon in this region of the nuclear chart. During the past years we have developed a new laser spectroscopic approach to determine the charge radii of lithium isotopes which combines high sensitivity, speed, and accuracy to measure the extremely small field shift of an 8 ms lifetime isotope with production rates on the order of only 10,000 atoms/s. The method was applied to all bound isotopes of lithium including the two-neutron halo isotope Li-11 at the on-line isotope separators at GSI, Darmstadt, Germany and at TRIUMF, Vancouver, Canada. We describe the laser spectroscopic method in detail, present updated and improved values from theory and experiment, and discuss the results.