Dependence of Dewar resonance energy of benzenoid molecules on Kekulé structure count

The dependence of the Dewar resonance energy (DRE) on the Kekulé structure count (K) was found to be significantly different from that earlier anticipated. Within classes of benzenoid isomers, the DRE increases either as Kl for l ~ 0.3 or as (ln K)l for l ~ 2. Both functional dependencies result in approximate expressions for DRE of nearly equal accuracy. Approximations of the form DRE ~ a K + b and DRE ~ a' ln K + b' are somewhat less accurate, but can still be used in usual practical applications of the Dewar resonance energy.