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

Paper SS-WeP17
The Diffusion of Single CO Molecules and Dimers on Pd(111)

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

Session: Surface Science Poster Session
Presenter: M.K. Rose, Lawrence Berkeley National Laboratory and University of California, Berkeley
Authors: T. Mitsui, Lawrence Berkeley National Laboratory
M.K. Rose, Lawrence Berkeley National Laboratory and University of California, Berkeley
E. Fomin, Lawrence Berkeley National Laboratory and University of California, Berkeley
D.F. Ogletree, Lawrence Berkeley National Laboratory
M. Salmeron, Lawrence Berkeley National Laboratory
Correspondent: Click to Email
The diffusion of individual CO molecules on Pd(111) has been studied by scanning tunneling microscopy in the temperature range 40-50 K. By following the random walk motion as a function of temperature an activation energy barrier of 0.116 ± 0.005 eV and a pre-exponential factor of 10@super -3.5@ cm@super 2@-sec@super -1@ were determined. Attractive interactions between CO molecules give rise to the formation of dimers that diffuse as a unit. Diffusion rates for dimers and energy parameters for the pair potential between CO molecules were also obtained. Coadsorbed hydrogen more than doubles the diffusion barrier of CO monomers.