Intensities in the Stark Effect of Helium: II

The intensities of the new spectral lines appearing in an electric field may be calculated from the quantum theory of perturbations. To apply the method to helium we consider the helium atom a perturbed hydrogen atom. Calculations are given here for a number of helium lines whose intensities have previously been measured. Measurements of the intensities of the groups $2S-nM$ and $2s-nm$ for $n=4, 5, 6$, and $M=S, P, D$, etc. are given and compared with the calculated intensities. The theory gives intensities of the correct order of magnitude and gives the variation with field approximately correctly but large deviations from the experimental values appear in all groups.