Lee Insup, Son Seungbae, Shin Taeho, Hahn Jae R
Department of Chemistry and Bioactive Material Sciences and Research Institute of Physics and Chemistry, Chonbuk National University, Jeonju 561-756, South Korea.
Jeonju Center, Korea Basic Science Institute, Jeonju 561-756, South Korea.
J Chem Phys. 2017 Jan 7;146(1):014706. doi: 10.1063/1.4973379.
The transition between two conformations of pyridine molecules adsorbed on a Ag(110) surface at 13 K was investigated by performing single-molecule manipulation at a very low coverage and the track-imaging of pyridines for various surface coverages using a variable low-temperature scanning tunneling microscope. A single tilted conformer was converted to an upright conformer when another coadsorbed tilted pyridine molecule approached to within ∼2 nm. The conversion probability depends on the molecular separation. The tilted conformers that are prevalent at a very low coverage were converted to upright conformers with an increasing surface coverage. The minimum molecular separation before this transition is induced was determined to be 2.2 nm using molecular track-imaging and statistical analysis of the pyridine separation as a function of the molecular coverage. The conformation transition was attributed to substrate-mediated long-range repulsive interactions between the pyridine molecules, which are produced by charge redistribution that occurs upon pyridine adsorption on the silver surface.
通过在极低覆盖率下进行单分子操纵，并使用可变低温扫描隧道显微镜对不同表面覆盖率的吡啶进行轨迹成像，研究了13K下吸附在Ag(110)表面的吡啶分子两种构象之间的转变。当另一个共吸附的倾斜吡啶分子靠近到约2nm以内时，单个倾斜构象体会转变为直立构象体。转变概率取决于分子间距。在极低覆盖率下普遍存在的倾斜构象体随着表面覆盖率的增加而转变为直立构象体。利用分子轨迹成像以及作为分子覆盖率函数的吡啶间距统计分析，确定了诱导这种转变之前的最小分子间距为2.2nm。构象转变归因于吡啶分子之间由吡啶吸附在银表面时发生的电荷重新分布所产生的底物介导的长程排斥相互作用。
