′�?, which has a frequency of 295 cm−one, is attributed to the stretching vibration of Ga–Se bonds. The two-phonon absorption with the 295 cm−one phonon corresponds to the crystal IR absorption edge, as opposed to the residual absorption peak. Density functional concept computations display the residual absorption on the BGSe https://baga4se7-crystal13567.blogsidea.com/39155433/baga4se7-crystal-options