′�?, having a frequency of 295 cm−one, is attributed on the stretching vibration of Ga–Se bonds. The 2-phonon absorption of your 295 cm−one phonon corresponds on the crystal IR absorption edge, instead of the residual absorption peak. Density functional principle computations exhibit that the residual absorption in the BGSe crystal https://baga4se7crystal06272.getblogs.net/65311756/baga4se7-crystal-an-overview