′�?, with a frequency of 295 cm−1, is attributed to the stretching vibration of Ga–Se bonds. The 2-phonon absorption on the 295 cm−1 phonon corresponds to your crystal IR absorption edge, rather then the residual absorption peak. Density functional idea computations exhibit that the residual absorption of your BGSe crystal https://baga4se7-crystal66393.qowap.com/92016964/about-baga4se7-crystal