Computer modeling of the structure of large molecules: III. Local excitations in the structure of 2D C60(XII) and C60(VIII) polymers

The quantum-chemical PM3 method was used to determine the structure of excited poly-C₆₀(XII) and poly-C₆₀(VIII) macromolecules containing diradical defects formed by cleavage of interpolyhedral C-C bonds and degradation of intrapolyhedral C=C bond. The relative energies of such excitations are estimated. The atomic free valences F _A hybridization coefficients of valence-active atomic orbitals contributing maximum F _a ≈ F _A to the F _A value are calculated. The valent isomerism of the C₆₀(XII) dodecaradical is discussed. The calculations are performed using the GAMESS computer program and a new SDIAG algorithm for diagonalization of large dense symmetric matrices.