Region of the He I line at 4471 Å and of the Mg II line at 4481 Å for the four stars in NGC 6752. The upper two spectra belong to stars without evidence for diffusion and the lower two show stars with evidence for diffusion. The spectrum of B2281 shows clear signs of rotation, while the situation for B652 is less clear. The offsets in line position indicate deviations of the star’s radial velocity from that of the globular cluster.