Computer modeling of the structure of large molecules: II. Cluster C1500

The structure of a C₁₅₀₀ cluster modeling a “planar” polymeric buckminsterfullerene(VIII) is determined by the PM3 quantum-chemical method. The cluster consists of 25 oblate octa-, hexa-, and tetra-valent C₆₀ polyhedra and has D _2h symmetry. The calculated parameters of a rectangular unit cell are as follows: 9.016 Å along the bridging bonds in the polymer plane and 9.084 Å along the bridging bonds over and under the polymer plane. Hybrid σ orbitals of three-coordinate atoms are directed at an angle of 9.7°–9.8° to the polyhedron edges and those of four-coordinate atoms, at an angle of 8.3°–8.6° to the rectangular bridge edges. The s contribution into π orbitals is negligibly small. The GAMESS program with a new algorithm for diagonalization of large dense symmetrical matrices and a new VALENCY program were used for calculations.