Improved quantum mechanical treatment of plasma polarization shift of ion lines

An improved quantum mechanical treatment of the plasma polarization shift of ion lines is presented. Calculations using this treatment are made for plasma conditions corresponding to available measurements of the shift of the He II resonance series. Comparisons with the other theories are also discussed. It is shown that the present treatment agrees with the experimental results obtained at low density but large discrepancies are found at high density. Moreover, there is good agreement with a corrected version of the semiclassical treatment of the effect but discrepancies of about one order of magnitude are obtained with the only quantum treatment presently available for resonance lines.