′�?, by using a frequency of 295 cm−1, is attributed for the stretching vibration of Ga–Se bonds. The two-phonon absorption with the 295 cm−1 phonon corresponds to the crystal IR absorption edge, rather than the residual absorption peak. Density purposeful principle computations present which the residual absorption in the BGSe https://knoxmwyup.uzblog.net/about-baga4se7-crystal-46674237