Structure and stability of Al₁₃H_n (n=1-13) clusters: Exceptional stability of Al₁₃H₁₃

We have performed density functional calculations for the structure and stability of Al₁₃H_n (n=1-13) clusters. Population analysis has shown significant charge transfer occurring from the Al cluster to the H atoms. The population for Al₁₃ varies from 0.24 (Al₁₃H) to 2.83 (Al₁₃H₁₃). The shape of Al₁₃ moieties in the Al₁₃H_n (n ≥ 8) clusters is significantly distorted from the icosahedral structure of Al₁₃ and is a "cagelike" form. Al₁₃H₁₃ has a capped icosahedron as the ground-state structure, similar to B₁₃H₁₃, while the shape of B ₁₃ (planar) is different from Al₁₃ (icosahedral). The Al₁₃H₁₃ cluster is predicted to be exceptionally stable on the basis of the high stabilization energy and the negative nucleus independent chemical shift value.