Pu Qing, Leng Yongsheng, Zhao Xiongce, Cummings Peter T
Department of Chemical Engineering, Vanderbilt University, Nashville, TN 37235, USA.
Nanotechnology. 2007 Oct 24;18(42):424007. doi: 10.1088/0957-4484/18/42/424007. Epub 2007 Sep 13.
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.
通过分子模拟进一步研究了溶剂对金纳米线伸长的影响。对于简单的 Lennard-Jones 溶剂（丙烷），它是一种非键合溶剂，大量的分子动力学（MD）模拟表明，在金纳米线熔点以下，溶剂对金纳米线伸长性能的影响最小。在硫醇有机液体中，例如在苯二硫醇（BDT）中，由于金 - BDT 化学键的存在，情况要复杂得多。在此，我们通过巨正则蒙特卡罗（GCMC）模拟展示了 BDT 在拉伸的金纳米线上的初始吸附结构。模拟中采用了最近开发的用于 BDT - 金化学键的力场。我们发现，键合的 BDT 在金纳米线表面的堆积密度大于在扩展的 Au(111) 表面上的堆积密度。这项工作的结果有助于理解在分子电导测量中实现的 Au - BDT - Au 结形成的潜在机制。
