′�?, having a frequency of 295 cm−1, is attributed to your stretching vibration of Ga–Se bonds. The 2-phonon absorption on the 295 cm−1 phonon corresponds to the crystal IR absorption edge, rather then the residual absorption peak. Density useful theory computations present that the residual absorption on the BGSe crystal https://baga4se7crystal41888.total-blog.com/baga4se7-crystal-an-overview-57907414