′�?, which has a frequency of 295 cm−1, is attributed towards the stretching vibration of Ga–Se bonds. The two-phonon absorption of the 295 cm−1 phonon corresponds towards the crystal IR absorption edge, as an alternative to the residual absorption peak. Density functional concept computations clearly show that the residual absorption https://eduardoihasl.dm-blog.com/32695716/baga4se7-crystal-an-overview