′�?, using a frequency of 295 cm−1, is attributed to the stretching vibration of Ga–Se bonds. The two-phonon absorption from the 295 cm−1 phonon corresponds to your crystal IR absorption edge, in lieu of the residual absorption peak. Density useful concept computations show the residual absorption from the BGSe crystal https://baga4se7crystal73051.blogsmine.com/33254835/5-tips-about-baga4se7-crystal-you-can-use-today