The reflectivity spectra of Hg1-xCoxSe (z = 0.0, 0.024, 0.031) crystal
s were measured in the vacuum ultraviolet photon energy range from 4 t
o 12 eV to find the influence of Co ions on the valence band electroni
c structure of the HgSe crystal. The structure of the reflectivity spe
ctra was interpreted in terms of the electronic band structure of the
binary material (HgSe) assuming direct allowed interband transitions.