′�?, using a frequency of 295 cm−one, is attributed for the stretching vibration of Ga–Se bonds. The 2-phonon absorption in the 295 cm−one phonon corresponds on the crystal IR absorption edge, as an alternative to the residual absorption peak. Density practical concept computations display the residual absorption on the BGSe https://baga4se7crystal18406.ziblogs.com/32562936/baga4se7-crystal-an-overview