′�?, by 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, as opposed to the residual absorption peak. Density practical concept computations demonstrate the residual absorption on the BGSe https://israeljvvso.theisblog.com/32672126/baga4se7-crystal-an-overview