title: Topological definition of ring currents.
abstract: A definition of ring currents in a velocity vector field is proposed according to topological criteria: ring currents are axial vortices confined in, or rotating beyond, a separatrix, i.e., the boundary which marks the limits of the vortex. Its possible extension to magnetic-field induced, delocalized electron flow in atoms, small non-cyclic molecules and aromatic cyclic compounds is considered.
authors.affiliation: Dipartimento di Scienze Chimiche e Geologiche, Università degli Studi di Modena e Reggio Emilia, via Campi 213/b, 41125 Modena, Italy. lazzeret@unimore.it.
authors.forename: Paolo
authors.initials: P
authors.lastname: Lazzeretti