Magic Cluster Anion LaCu₁₂^-: From Superatomic Electronic Structure to Spherical Aromaticity

In this work, we systematically investigate the structural evolution and stability of lanthanum-doped copper cluster anions LaCu_n^- (n = 1-16) via unbiased global structure search and density functional theory (DFT) calculations. Among these clusters, species at multiple sizes exhibit enhanced energetic stability, whereas LaCu₁₂^- is structurally distinguished by its compact half-cage geometry. Complementary Mulliken population analysis and energy decomposition analysis (EDA) reveal that the central La atom donates its valence electrons to the surrounding Cu cage, giving rise to the 16-electron superatomic closed-shell configuration that underpins the cluster stability. Adaptive natural density partitioning (AdNDP) analysis confirms that this exceptional stability originates from multicenter delocalized bonds spanning the entire Cu cage; meanwhile, isochronous chemical shielding surface (ICSS_zz) analysis uncovers strong spherical aromaticity, as evidenced by a pronounced shielding peak at 193 ppm. These findings elucidate the synergistic effect between electrostatic attraction and superatomic electronic shell closure and provide theoretical guidance for the rational design of rare-earth-doped superatomic clusters toward functional material applications.