Electronic structure and luminescence properties of Ca2Ge7O16:Dy3+I.I. Leonidov, A.V. Ishchenko, E.I. Konstantinova, V.P. Petrov, V.A. Chernyshev and A.E. NikiforovEPJ Web Conf., 132 (2017) 03027DOI: https://doi.org/10.1051/epjconf/201713203027