This paper overviews our recent results on the magneto-optics of excitons in wide quantum
wells, when the well width is much larger than the exciton Bohr radius. We have demonstrated
that the magnetic moment of the exciton increases by an order of magnitude due to its motion
along the magnetic field. The effect was observed for a set of quantum well structures with
different well widths and based on various semiconductor compounds. The reason for this
effect is mixing of the exciton’s center-of-mass motion and the internal motion of electron and
hole in the exciton.