Ring current models for acetylene and ethylene molecules

Spatial models of the current density vector field, induced in theelectronic cloud of the acetylene and ethylene molecules by a uniform,time-independent magnetic field, are discussed in terms of topologicalstagnation graphs and three-dimensional streamline plots. The modelsare validated by documenting their ability to explain magnetic suscep-tibility and nuclear magnetic shieldings of carbon and hydrogen viarelated shielding density maps.