Good Morning, Dear users of SIESTA, I am studying the optical properties of structures based on boron nitrides (ribbons). However, there are some structures that have an indirect gap (appearance of phonons), I am working on 0K. So my question has arisen, does SIESTA calculate optical transitions in systems with indirect gap? I've looked in literature, but I still do not know the answer. Could you please tell me an article or a book? I know that it uses first-order pertubative calculations and the approximation of the electric dipole in the calculation of optical transitions.
Thank you !!! -- " A sabedoria da natureza é tal que não produz nada de suférfluo ou inútil". Nicolau Copérnico Osmar Francisco
