3 research outputs found
The Orbital Selection Rule for Molecular Conductance as Manifested in Tetraphenyl-Based Molecular Junctions
Using
two tetraphenylbenzene isomers differing only by the anchoring points
to the gold electrodes, we investigate the influence of quantum interference
on the single molecule charge transport. The distinct anchor points
are realized by selective halogen-mediated binding to the electrodes
by formation of surface-stabilized isomers after iodine cleavage.
Both isomers are essentially chemically identical and only weakly
perturbed by the electrodes avoiding largely parasitic effects, which
allows us to focus solely on the relation between quantum interference
and the intrinsic molecular properties. The conductance of the two
isomers differs by over 1 order of magnitude and is attributed to
constructive and destructive interference. Our ab initio based transport
calculations compare very well with the accompanying scanning tunneling
microscope break junction measurements of the conductance. The findings
are rationalized using a two level model, which shows that the interorbital
coupling plays the decisive role for the interference effects