The aim of the present study is to extend the multiconfiguration Dirac-Fock approach to include spin polarization in order to study magnetically ordered systems. Routines handling time-dependent ionization phenomena adapted to multilevel and multichannel autoionization processes have been developed and used to describe the giant resonance in the Gd³⁺ absorption spectrum. In our calculation of the complete energy structure of 4d⁹4f⁸ configuration it is discovered that the majority of the oscillator strength associated with the 4d-4f transitions is limited to a relatively narrow spectral width, creating a giant resonance. Our calculations take account of the most important correlation effects, and the agreement with the experimentally observed giant resonance in gadolinium is quite good.