Circular currents in Molecular Wires.

Circular current in molecules is more characteristic in species that have circular structures, such as rings. When  a current is applied an interesting phenomenon is observed, depending on the molecular structure framework it will allow circular currents. These type of measurementes and observations are limited to computational theoretical analysis. Depending on the characteristics of the system that is being analyzed, the results may differ. 

For example, circular currents often appear in certain voltage regimes in junctions characterized by multiple pathways that may close within a given molecular bridge to give a circular pathway. In other cases, the voltage of the circular current can be larger than the net junction current. Another different result was that a t a strong circular current can appear near conduction thresholds in the current.

In the isolated ring these orbitals are degenerate,and are characterized by equal and opposite orbital angular momentum along the molecular ring. such circular currents are found to be associated with considerable magnetic fields at the center of the ring. Analogous effects in molecules were discussed extensively in the context of molecular magnetic response, in particularas the origin of magnetic shielding phenomena in NMR spectroscopy.

Fuente: Rai, D. et al. (2010). Circular current in Molecular Wires. Recuperado el 11 de mayo de 2013, de 

http://www.tau.ac.il/~odedhod/papers/paper21.pdf