A Raman spectroscopic investigation of Fe-rich sphalerite: effect of fe-substitution

A Raman spectroscopic study of Fe-rich sphalerite ( Zn1-xFexS) has been carried out for six samples with 0.10 <= x <= 0.24. Both the intensities and frequencies of the TO and LO modes of sphalerite are approximately independent of Fe concentration. However, the substitution of Zn by Fe results in five additional bands with frequencies between the TO ( 271 cm(-1)) and LO ( 350 cm(-1)) modes. Three of these bands are attributed to resonance modes ( i. e. Y-1, Y-2 and Y-3 modes). The fourth band ( B mode) is assigned to a breathing mode of the nearest-neighbor sulfur atoms around the Fe atoms. The band at 337 cm(-1) is attributed to the presence of Fe3+. The excellent correlations between the normalized intensities of these five different modes and chi(Fe) show that these modes depend on Fe-content. Another extra mode at 287 cm(-1) is assigned to the presence of Cd in sphalerite.