AVS 47th International Symposium
    Surface Science Wednesday Sessions
       Session SS2+VT-WeA

Paper SS2+VT-WeA7
STM Investigation of Benzene Adsorption on Ag(110)

Wednesday, October 4, 2000, 4:00 pm, Room 209

Session: Adsorption and Desorption Phenomena I
Presenter: K.F. Kelly, Pennsylvania State University
Authors: K.F. Kelly, Pennsylvania State University
J.J. Jackiw, Pennsylvania State University
J.I. Pascual, Fritz Haber Institute, Germany
H. Conrad, Fritz Haber Institute, Germany
H.-P. Rust, Fritz Haber Institute, Germany
P.S. Weiss, Pennsylvania State University
Correspondent: Click to Email
We have investigated the adsorption of benzene on Ag(110) using the scanning tunneling microscope. We found that the molecules preferentially adsorb above step edges at 66 K. The preference for step edge adsorption is attributed to the Smoluchowski effect enhancing the empty states to which charge is donated from the @pi@ orbitals of the benzene. However, there is no adsorption at the [001] steps. A lack of free charge due to a gap in the Ag Fermi surface along that direction reduces the Smoluchowski effect and thus the adsorption at these steps. After further deposition at 4 K, we find that benzene forms a weakly adsorbed hexagonal monolayer. The monolayer is imaged at large tip-sample separations and is transparent upon closer approach. The interaction of benzene molecules with steps and point defects reduces this transparency.