Structure and stability of Al₁₃I clusters

We have performed density functional calculations for the structures and stabilities of Al₁₃I at the scalar relativistic pseudopotential and all-electron levels of theory. The Al₁₃ moiety in Al₁₃I is significantly distorted and structurally similar to an Al₁₃ cation, where the natural population is -0.27e for the I atom. Unlike other Al ₁₃-M (M = H, alkali metals, and coinage metals) clusters, a C _s -ontop structure was found to be the most stable form. The Al ₁₃I cluster has a large Al₁₃-I binding energy of 3.11 eV and is more stable, as charge transfer to the electronegative I atom is larger.