AVS 49th International Symposium
    Surface Science Wednesday Sessions
       Session SS-WeP

Paper SS-WeP11
Low Temperature STM Investigation of Halosubstituted Biphenyls on Copper Surfaces

Wednesday, November 6, 2002, 11:00 am, Room Exhibit Hall B2

Session: Surface Science Poster Session
Presenter: L. Bartels, University of California at Riverside
Authors: L. Bartels, University of California at Riverside
B.V. Rao, University of California at Riverside
Q. Zhang, University of California at Riverside
Correspondent: Click to Email
4,4'-Di-bromo-biphenyl was adsorbed on a Cu(111) single crystal surface in ultra-high vacuum at 25K. The preferred adsorption site and the mobility of the species were investigated. 4,4'-Di-bromo-biphenyl was found to adsorb primarily at step edges on the surface with the long axis of the molecule aligned parallel to the step edge. High-resolution images reveal the individual, substituted benzene rings. Their separation is in good agreement with the value expected from the literature. In contrast, adsorption at nitrogen temperatures does not permit STM investigation of the unreacted species on the surface. STM images are poor and high fluctuations in the tunneling current point to a mobility of the adsorbate beyond the time-scale of the feedback loop. Retracting the tip several nanometers from the sample, the tunneling current does not vanish completely in a reliable fashions. This points to the spontaneous polymerization of 4,4'-di-bromo-biphenyl to long tethers on the surface.