Chapter 4 Studies of Light Halo Nuclei from Atomic Isotope Shifts

Abstract

Abstract This paper reviews progress in the application of atomic isotope shift measurements, together with high precision atomic theory, to the determination of nuclear radii from the nuclear volume effect. The theory involves obtaining essentially exact solutions to the nonrelativistic three- and four-body problems for helium and lithium by variational methods. The calculation of relativistic and quantum electrodynamic corrections by perturbation theory is discussed, and in particular, methods for the accurate calculation of the Bethe logarithm part of the electron self energy are presented. The results are applied to the calculation of isotope shifts for the short-lived ‘halo’ nuclei 6He and 11Li in order to determine their nuclear charge radii from high precision spectroscopic measurements. It is shown that the results provide a unique measurement tool that is capable of discriminating amongst a variety of theoretical models for nuclear structure. In view of the high precision that is now obtainable, helium and lithium, along with hydrogen, can be regarded as fundamental atomic systems whose spectra are well understood for all practical purposes.