Topology of the Electronic Current Density Induced by a Static Magnetic Field in Lithium Hydride, Water, Ammonia and Methane Molecules

The current density JB, induced by a time-independent, spatially uniform magnetic field B in the electron cloud of a molecule, is characterized by peculiar topological features. The fundamental elements for the topological analysis of the JB(r) vector field are the stagnation points (SP) at which it vanishes. One-dimensional manifolds of stagnation points are named stagnation lines (SL). The set of all SPs and SLs constitute the stagnation graph (SG) of the current density vector field. An SG yields exhaustive information on JB(r) in compact form, as exemplified by accurate calculations on a few small molecules at DFT level of approximation.