SCF MO calculations of tropone,tropolone and related compounds

The variable-β procedure of the semiempirical SCF MO method was applied to tropone, tropolone and related compounds. Although the bond alternation in the heptagonal ring is neglected in the initial molecular geometry, the predicted transition energies show a good agreement with experiment, indicating the utility of this method for the calculation of the electronic spectra of non-benzenoid aromatic compounds. Discussions are given on the assignments of the absorption bands of tropone and tropolone.