Time:9:00-9:40 am,Saturday,November 14,2020

Tencent Meeting ID：567 684 538

Speaker:Professor Zhang Yang

Organizer:School ofMechanical Engineering, Hefei University of Technology

Introduction

Vibronic coupling plays an important role in the profile of optical bands as well as intermolecular interaction and energy transfer. Molecular optical spectroscopy is an ideal tool to investigate the influence of molecular vibrations on the electronic transitions. However, due to the diffraction limit in conventional optics, it is highly challenging to offer a straightforward microscopic picture on the vibronic coupling in real space.

The tunneling electrons in a scanning tunneling microscope (STM) induced luminescence (STML) technique, combining the STM with optical detection, can do nano-imaging beyond diffraction limit, which provide photon images with spatial resolution down to sub-nanometer scale.

By exploiting the STML technique, we demonstrate the visualization of vibronic coupling in a single pentacene molecule. The molecular electroluminescence of a single pentacene molecule exhibits rich vibronic modes and excitation position-dependent features. The sub-nanometer revolved spectroscopic imaging patterns for different vibronic modes show different symmetry. Combining with the DFT calculations, such difference in imaging patterns can directly reveal the microscopic picture that how the molecular vibrations influence the electronic motions and the associated transition dipoles. Our results not only provide an example for the straightforward understanding on vibronic coupling in real space, but also open up new route to investigate the influence of vibronic coupling on electronic states and intramolecular energy transfer at single-molecule level.

More details:http://jxxy.hfut.edu.cn/2020/1113/c9184a240556/page.htm