′�?, using a frequency of 295 cm−1, is attributed to your stretching vibration of Ga–Se bonds. The 2-phonon absorption of your 295 cm−one phonon corresponds towards the crystal IR absorption edge, rather than the residual absorption peak. Density functional theory computations exhibit which the residual absorption with the BGSe crystal https://baga4se7crystal72592.ezblogz.com/64306600/baga4se7-crystal-an-overview