′�?, with a frequency of 295 cm−1, is attributed into the stretching vibration of Ga–Se bonds. The two-phonon absorption with the 295 cm−one phonon corresponds on the crystal IR absorption edge, rather then the residual absorption peak. Density functional concept computations show which the residual absorption on the BGSe crystal https://baga4se7crystal86296.blogoxo.com/32590000/baga4se7-crystal-options