Calculation of the photo-electrons angular distribution asymmetry parameter β2p near the (3s3p)Ip resonance of He

Near the (3s3p)1p resonance of He, we have calculated the photo-electrons angular distribution asymmetry parameter β2p in the diagonalization approximation. Using the measured value of βn=2 near the (3s3p)1p level obtained by Lindle et al. in the resonance photo-ionization of He to He+(n=2), we have estimated the ratio R=σ2p/σ2s of the partial 2p photo-ionization cross section to the partial 2s photo-ionization cross section. Our calculation supports the result that in the resonance region, the formation of ions in the 2p level dominates over the 2s level. This is in good agreement with the experimental and most of the theoretical results reported to date. (author). 18 refs, 1 fig., 2 tabs