On Local Simulations of Local Fluxes in Molecular Juncitons

We present a pedagogical review of the current density simulation in molecular junction models indicating its advantages and deficiencies in the analysis of local junction transport characteristics. In particular, we argue that current density is a universal tool which provides more information than traditionally simulated bond currents, especially when discussing inelastic processes. On the other hand, current density simulations are sensitive to the basis set and the electronic structure method utilized. We note that while discussing the local current conservation in junctions, one has to account for the source term caused by the open character of the system and intra-molecular interactions. Our considerations are illustrated with numerical simulations of a benzenedithiol molecular junction.