Infrared active crystal-field (CF) excitations, between the I-4(9/2) and I-
4(11/2) manifold electronic levels of the Nd3+ ions, have been studied in N
d2-xGdxCuO4 at 4.2 K. The influence of the Gd3+ substitution on the infrare
d active CF excitations has been determined by comparison with the CF excit
ations of the parent undoped Nd2CuO4 and cerium doped Nd1.85Ce0.15CuO4 comp
ounds.