All of the LFRS peaks observed prior to sulfur treatment agree with the previously reported modes, the vibrational symmetries of which are well documented in the literature. Upon sulfur treatment, two new AVM peaks emerge in the LFRS at 95.18 cm -1 and 141.41 cm -1 , corresponding to the simulated values of 94 cm -1 and 142 cm -1 , respectively. We believe that this is the first time these modes have been resolved optically. We also observe that sulfur treatment enhances the AVMs at 106.53 cm -1 and 118.83 cm -1 . Furthermore, the sulfur treatment induced a blue shift in the position of the LFRS peaks from 60.03 cm -1 , 84.81 cm -1 , 191.20 cm -1 and 256.03 cm -1 , observed prior to sulfur treatment, to lower wavenumbers of 59.05 cm -1 , 82.83 cm -1 , 189.74 cm -1 , and 253.07cm -1 , respectively. The LFRS peaks observed at 27.69 cm -1 , 42.65 cm -1 and 153.65 cm -1 match those of elemental sulfur. While the peak at 27.69 cm -1 can be attributed to the external surface vibrations of α-S8 and the peak at 42.65 cm -1 can be attributed to similar surface modes of γ-S8, the peak at 153.65 cm -1 is attributed to internal bond vibration of S8 as consistent with reports in the literature that all the allotropes of S8 have similar spectral feature at 153cm -1 . The changes we observe in the LFRS of Sb2Se3 can be attributed to defect passivation upon sulfur treatment.