′�?, having a frequency of 295 cm−one, is attributed to your stretching vibration of Ga–Se bonds. The 2-phonon absorption in the 295 cm−one phonon corresponds to your crystal IR absorption edge, as an alternative to the residual absorption peak. Density practical idea computations exhibit the residual absorption from the BGSe https://gunnersssmj.blogminds.com/detailed-notes-on-baga4se7-crystal-29855865