′�?, with a frequency of 295 cm−one, is attributed into the stretching vibration of Ga–Se bonds. The two-phonon absorption on the 295 cm−1 phonon corresponds on the crystal IR absorption edge, instead of the residual absorption peak. Density practical concept computations show which the residual absorption in the BGSe crystal https://baf-crystal24678.eedblog.com/32728169/considerations-to-know-about-baga4se7-crystal