Stokes Q/I (left panel), U/I (middle panel), and V/I (right panel) profiles for the He II Ly-α line as a function of wavelength. The results are obtained performing PRD-AD calculations for a LOS near the limb (μ = 0.1 and χ = 0) and with a uniform horizontal (θ_B = π/2 and χ_B = 0) magnetic field of 100 G. Blue, red, yellow, and purple lines correspond to profiles obtained with the FAL-A, FAL-C, FAL-F, and FAL-P atmospheric models, respectively.