New achievements in technology have made it possible to investigate th
e electronic band structure of the cubic form of mercury sulphide (bet
a-HgS). Reflectivity spectra of the HgSe1-ySy (y less than or equal to
0.75) ternary crystals have been measured in the energy range 1.5-12
eV. The results of a Kramers-Kronig analysis as well as conclusions on
the electronic band structure of beta-HgS are presented and discussed
.