Theory of the helium isotope shift

TL;DR

This paper reviews the theoretical understanding of helium isotope shifts, providing numerical predictions for specific transitions and accurately determining nuclear charge radius differences by comparing with experimental data.

Contribution

It offers a comprehensive theoretical analysis of helium isotope shifts and precise determination of nuclear charge radius differences from experimental comparisons.

Findings

Numerical results for helium isotope shifts are provided.

The difference in nuclear charge radii between helium isotopes is accurately determined.

Theoretical predictions align well with experimental data.

Abstract

Theory of the isotope shift of the centroid energies of light few-electron atoms is reviewed. Numerical results are presented for the isotope shift of the $2^3P$-$2^3S$ and $2^1S$-$2^3S$ transition energies of $^3$He and $^4$He. By comparing theoretical predictions for the isotope shift with the experimental results, the difference of the squares of the nuclear charge radii of $^3$He and $^4$He, $\delta R^2$, is determined with high accuracy.