A single molecule view of bistilbene photoisomerization on a surface using scanning tunneling microscopy
Journal
Journal of the American Chemical Society
Journal Volume
127
Journal Issue
31
Pages
10788-10789
Date Issued
2005
Author(s)
Abstract
The advent of scanning tunneling microscopy (STM) has permitted a detailed atomic view of organic molecules adsorbed on solid surfaces. In this work, we make use of the STM to provide an unprecedented direct single-molecule perspective on the cis-trans photoisomerization of stilbene molecules within ordered monolayers physisorbed on the Ag/Ge(111)-( radical3x radical3)R30 degrees surface. The STM view of the molecular structure transformation upon irradiation provides direct evidence for the generally accepted one-bond-flip mechanism proposed for the photoisomerization process. We also find that the surface environment produces a profound effect on the reaction mechanism. The reaction is observed to proceed mainly through pairs of co-isomerizing molecules situated at domain boundaries. To explain these observations, we propose a mechanism whereby excitation migrates to the domain boundary and the reaction occurs through a biexciton reaction pathway.
Publisher
American Chemical Society
Type
journal article