′�?, which has a frequency of 295 cm−1, is attributed to your stretching vibration of Ga–Se bonds. The two-phonon absorption of your 295 cm−1 phonon corresponds into the crystal IR absorption edge, rather than the residual absorption peak. Density functional idea computations exhibit the residual absorption from the BGSe crystal https://milorxzyx.blog-mall.com/33224372/not-known-details-about-baga4se7-crystal