MINDO/3 study of [18]annulene
Abstract
The geometry of [18]annulene has been calcuculated by minimising the energy with respect to all 102 internal co-ordinates, using the MINDO/2 and MINDO/3 semiempirical SCF MO methods; the bond lenghths are predicted to alternate, in agreement with calculations by the π approximation and molecular mechanics and the predicted heat of formation agrees with that from the π approximation, implying little aromatic stabilization.