title: Aromaticity rules for cycles with arbitrary numbers of half-twists.
abstract: A simple proof is given that the Hückel aromaticity rules generalise to cycles with an arbitrary number of half-twists, T; addition/removal of half-twists two at a time preserves all eigenvalues and degeneracies, so that closed-shell aromatic systems occur at pi-electron counts 4N+ 2, and antiaromatic at 4N for even T, and vice versa for odd T.
authors.affiliation: Department of Chemistry, University of Sheffield, Sheffield S3 7HF, UK. P.W.Fowler@sheffield.ac.uk
authors.forename: Patrick W
authors.initials: PW
authors.lastname: Fowler
authors.forename: Henry S
authors.initials: HS
authors.lastname: Rzepa
mesh_terms: D000465:Algorithms; D006841:Hydrocarbons, Aromatic / Q000737:chemistry*; D008956:Models, Chemical; D008968:Molecular Conformation; D015394:Molecular Structure
chemical_list: D006841:Hydrocarbons, Aromatic