Theoretical studies on electronic transportproperties of 2,5-dimercapto- pyridazin molecularjunctions: influence of CO and H 2O molecules
Based on first-principles calculations, the electrode force acted on 2,5-dimer
capto-pyridazin molecular device is studied. The pressing effects of CO and H_2O
molecules on the 2,5-dimercapto-pyridazin molecular junctions are also studied at
B3LYP level to simulate the effects of little ambient molecules on the functional molecular
junctions. The electronic transport properties of 2,5-dimercapto-pyridazinmolecular
junction with the pressing of CO and H_2O molecules are studied by employing
elastic scattering Green's function method. The numerical results show that the 2,5-
dimercapto-pyridazin can be squeezed out of the electrode gap when the electrode
distance is compressed to 1.02 nm. It is need about 1.5 nN stretching force to break
down the 2,5-dimercapto-pyridazinmolecular junction, which agrees with the experiment
probes very well. The 2,5-dimercapto-pyridazinmolecule is bent by the pressing
of CO or H_2O molecule, and is pushed to the edge of Au (111) triangles with the terminal
S atoms first to the bridge and then to the top positions of Au (111) triangles,
until at last one terminal S atom is pushed out of Au (111) triangle. The pressing
of CO and H_2O molecules to the molecular junctions will enhance the couplings between
molecule and electrodes, which further enhances nonresonant transmission of
the molecular junctions.
