σ-π energy separation in modern electronic theory for ground states of conjugated systems

The study of the σ-π energy separation in modern electronic theory for ground states of conjugated systems was presented. The discussion included a description of the π-electron methods, the importance of a rigorous σ-π separation methodology, estimation of the π-bonding energies and evidence for the σ-π interplay in the distortivity of delocalized systems. The study was important for the understanding of fundamental concepts such as conjugation, aromaticity, antiaromaticity and ring currents.