Molecular simulations of stretching gold nanowires in solvents

摘要

The effect of solvent on the elongation of gold nanowires has been further studied through molecular simulations. For a simple Lennard-Jones solvent (propane), which is a non-bonded solvent, extensive molecular dynamics (MD) runs demonstrated that below the melting point of gold nanowires, the solvent effect on the elongation properties of Au nanowires is minimal. In thiol organic liquid, such as in benzenedithiol (BDT), the situation is much more complicated due to the Au-BDT chemical bonding. Here, we present the initial adsorption structure of BDT on a stretched gold nanowire through grand canonical Monte Carlo (GCMC) simulations. A recently developed force field for the BDT-Au chemical bonding was implemented in the simulations. We found that the packing density of the bonded BDT on the surface of Au nanowire is larger than that on an extended Au(111) surface. The results from this work are helpful in understanding the underlying mechanism of the formation of Au-BDT-Au junctions implemented in molecular conductance measurements.