′�?, which has a frequency of 295 cm−1, is attributed to the stretching vibration of Ga–Se bonds. The two-phonon absorption in the 295 cm−1 phonon corresponds into the crystal IR absorption edge, rather then the residual absorption peak. Density useful theory computations clearly show the residual absorption on the BGSe https://baga4se7crystal05048.get-blogging.com/33281890/everything-about-baga4se7-crystal