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BYThe band structure of CdG%S4 is calculated by the pseudopotential method in /1/ and by the method of localized orbitals in /2/. According to the data of /1/ the top of the valence band meets the r2v representation, whereas according to /2/ it complies with r3v+ r4v. The conduction band bottoms in /1/ and /2/ a r e conform to the TlC representation.ly obtained data on the nature of optical transitions and their values in the fundamental absorption edge region a r e conflicting. In /6/ the reflection spectra within the fundamental absorption region (up to 6 eV) a r e presented without any interpretation. In /3 t o 5/ we studied the double reflection spectra of CdG%S4 in the region of 3 to 6 eV at polarized radiation and their interpretation was given on the basis of a group-theoretical analysis and a correlation with the optical spectra of compounds having chalcopyrite structure.The optical spectra of CdG%S4 have been studied in /3 to 7/. The previous-All the earlier measurements were conducted by stationary methods which did not allow to detect a fine structure. Therefore in this study the L -modulated reflection spectra have been investigated with polarized radiation at 300 K i n order to provide a more accurate picture of the band spectrum of Cdc%S4.pendence of the absorption coefficient on the energy of incident photons at polarized radiation. The presence of an isotropic point at h v = 3.38 eV where K , , = = K, is typical of this spectrum. In /6/ the dependence of the absorption coefficient on the energy of incident photons at polarised radiation is also presented but no isotropic point has been detected. The authors of /6/ apparently used thick specimens. Owik to the unambiguous relationship between the absorption coefficient and the refraction index, one may suppose that the observed depend-the region of the fundamental absorption edge of CdG%S4 (in Experimental results and their discussion The inset in Fig. 1 gives the de-1 ) Narimanova 33, Baku 143, USSR.

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