The structural, electronic and optical properties of CuGa (SexS1-x)2 compounds from first-principle calculationsKe-Sheng Shen, Zhao-Yong Jiao, Xian-Zhou Zhang and Xiao-Fen HuangEur. Phys. J. B, 86 11 (2013) 469DOI: https://doi.org/10.1140/epjb/e2013-40736-4