POLARIZATION OF LIGHT FROM COLLISION OF A PROTON BEAM WITH HELIUM ATOMS

We have measured the relative cross-sections and the polarization of the light resulting from the excitation of helium by a proton beam for the following transitions: 3 D1→2 P1(λ=6678), 3 S1→2 P1(λ=7281), 3 D3→2 P3(λ=5876), 3 S3→2 P3(λ=7065). Our analysis indicates that there is a small violation of the ΔS=0 spin rule for the excitation of the 3D3 and 3S3 states of helium by protons. © 1968 The American Physical Society.