′�?, using a frequency of 295 cm−1, is attributed for the stretching vibration of Ga–Se bonds. The two-phonon absorption in the 295 cm−1 phonon corresponds towards the crystal IR absorption edge, instead of the residual absorption peak. Density functional idea computations clearly show the residual absorption in the BGSe crystal https://aggas2-crystal51962.buyoutblog.com/32651721/baga4se7-crystal-an-overview