Semiempirical vibrational and electronic structures of C₆₀ and C₇₀

Abstract

Abstract The electronic and vibrational structures of C 60 and C 70 have been calculated at the PM3 semiempirical level. C 60 has a partially delocalized structure, while C 70 has both a localized set and a delocalized set of MOs. As with AM1 and MNDO, PM3 predicts the heat of formation of C 70 to be greater than that of C 60 , and that C 70 is the thermodynamically more stable species. Calculation of the normal modes was accelerated over 40 times by limited use of symmetry theory.