The diffusion of CO on Pt(111) was simulated, for temperatures ranging from 100 to 500K, by using molecular dynamics methods. Both static and dynamic (111) surfaces were used. For both surfaces, the displacement and the velocity auto-correlation of a single trajectory were compared for 2 initial kinetic energies. The effects of the internal states of the CO molecule were also studied. The results showed that both rotational and vibrational motion affected the surface diffusion behavior in this system. The simulated diffusivity of the CO molecule on a clean (111) surface exhibited good agreement with recent experimental data. The diffusion energy barrier which was predicted by the simulation was 5.8kcal/mol. This was in excellent agreement with the experimental value of 6kcal/mol. The pre-exponential factor was equal to 0.00033cm2/s.

L.Wang, Q.Ge, G.D.Billing: Surface Science Letters, 1994, 304[1-2], 413-9