Kazuma Emiko, Han Mina, Jung Jaehoon, Oh Junepyo, Seki Takahiro, Kim Yousoo
Surface and Interface Science Laboratory, RIKEN , Wako, Saitama 351-0198, Japan.
Department of Molecular Design and Engineering Graduate School of Engineering, Nagoya University Furo-cho , Chikusa, Nagoya 464-8603, Japan.
J Phys Chem Lett. 2015 Nov 5;6(21):4239-43. doi: 10.1021/acs.jpclett.5b01847. Epub 2015 Oct 12.
The predominant pathway for the isomerization between cis- and trans-azobenzenes-either (i) inversion by the bending of an NNC bond or (ii) rotation by the torsion of two phenyl rings-continues to be a controversial topic. To elucidate each isomerization pathway, a strategically designed and synthesized azobenzene derivative was investigated on a Ag(111) surface. This was achieved by exciting the molecule with tunneling electrons from the tip of a scanning tunneling microscope (STM). Structural analyses of the molecularly resolved STM images reveal that both inversion and rotation pathways are available for isomerization on a metal surface and strongly depend on the initial adsorption structures of the molecule. On the basis of the potential energy diagrams for the isomerization, it is concluded that isomerization pathways on a metal surface are not simply related to the excited states.
顺式和反式偶氮苯之间异构化的主要途径——（i）通过NNC键的弯曲进行反转或（ii）通过两个苯环的扭转进行旋转——仍然是一个有争议的话题。为了阐明每种异构化途径，对一种经过精心设计和合成的偶氮苯衍生物在Ag(111)表面进行了研究。这是通过用扫描隧道显微镜（STM）尖端的隧道电子激发分子来实现的。对分子分辨STM图像的结构分析表明，反转和旋转途径在金属表面都可用于异构化，并且强烈依赖于分子的初始吸附结构。根据异构化的势能图，得出结论：金属表面的异构化途径与激发态并非简单相关。
