A density functional study on the shape of C₁₈₀ and C₂₄₀ fullerenes

At the gradient-corrected BP86/SV level of density functional theory, the fully optimised, facetted geometry of I_h-C₁₈₀ is 126 kcal/mol lower in energy than an optimised spherical structure where all atoms are constrained to lie on the same sphere. Likewise, using MNDO geometries, facetted I_h-C₂₄₀ is more stable than the constrained spherical form by 203 and 202 kcal/mol at the non-local BP86/SV and the local VWN/SV levels, respectively. These findings are at variance with predictions from local density functional calculations employing the divide-and-conquer approximation and the Harris functional, but confirm the results of recent MNDO and ab initio SCF studies