A Density Functional Theory Study on Nonlinear Optical Properties of Double Cage Excess Electron Compounds: Theoretically Design M[Cu(Ag)@(NH3)n](M = Be, Mg and Ca; n = 1-3). - Yan Ying Liang; Bo Li; Xuan Xu; Feng Long Gu; Chaoyuan Zhu (J. Comput. Chem., 2019)