Mass-polarization effects in the 1s2s 1S and 3S states of helium.

Abstract

From a laser spectroscopic study of isotope shifts in the 1s2s $^{1}$S${,}^{3}$S\ensuremath{\rightarrow}1snp transitions in $^{3}\mathrm{He}$ and $^{4}\mathrm{He}$ and of the hyperfine structure in the 1snp Rydberg states of $^{3}\mathrm{He}$ we have derived highly accurate information on mass-polarization effects in the 1s2s $^{1}$S and $^{3}$S states. The experimental results, which are in good agreement with recent, high-precision variational calculations, confirm an isotope dependence of 〈${\mathbf{p}}_{1}$\ensuremath{\cdot}${\mathbf{p}}_{2}$〉. .AE