A quantified resonance theory and its relation with MO — excited state behaviour of conjugated hydrocarbons and heteroconjugate molecules

Summary Quantified resonance theory (QRT) involving the use of weight has been applied successfully to ionization potential, electron affinity, energy of the lowest * transition, charge density and bond order in excited state for alternant and nonalternant hydrocarbons and heteroconjugate molecules. A number of close relations between QRT and HMO or PMO are found. QRT naturally leads to the frontier orbital theory results, and the natural hypsochromic shift in electronic spectra of fulvenes is also explained satisfactorily.