The effect of the vibrational free energy upon self-diffusion on the (100) surface was considered within the framework of transition state theory. The local thermodynamic functions were deduced from vibrational density of states that were extracted by using interaction potentials that were based upon the embedded atom method. It was found that as the temperature increased to 600K vibrational contributions led to a decrease in the pre-exponential factor of about 2 orders of magnitude, to a lowering of the barriers by about 10%, and to an increase in the activation free energy of about 20%. There was a marked net effect upon the diffusion constant.

U.Kürpick, A.Kara, T.S.Rahman: Physical Review Letters, 1997, 78[6], 1086-9