Ultraviolet inverse-photoemission spectroscopy of Gd silicides

Empty electronic states of gadolinium silicides (${\mathrm{Gd}}_3$ ${\mathrm{Si}}_5$ and ${\mathrm{Gd}}_5$ ${\mathrm{Si}}_3$) are investigated by means of inverse photoemission in the ultraviolet photon range. Isochromat spectra taken at different photon energies (11–25 eV) are presented. The results are discussed in terms of bond formation between metal and silicon orbitals, in analogy with silicides of other low-d-occupancy metals (Ca silicides).