′�?, that has a frequency of 295 cm−one, is attributed for the stretching vibration of Ga–Se bonds. The two-phonon absorption in the 295 cm−1 phonon corresponds to the crystal IR absorption edge, instead of the residual absorption peak. Density functional idea computations exhibit the residual absorption on the BGSe crystal https://fernandomnkez.win-blog.com/12866492/baga4se7-crystal-an-overview