The contact conductance on a molecular wire

On a metal-molecule-metal nanojunction, the scanning tunneling microscope (STM) scans at the precise location of the electronic metal-molecule interaction permit a measurement of the contact conductance G0. The conversion curve between the change in the STM contrast Δh due to this interaction and G0 is presented for a series of conjugated molecular wires. At chemisorption distances, the two-valued character of the G0(Δh) function is discussed, indicating experimental ways to evaluate G0 as a function of Δh for different metal-molecule interaction ranges.