Determination of interlayer diffusion parameters for Ag/Ag(111)

It is well known that the Ag/Ag(lll) epitaxial system grows three dimensionally because of the existence of a relatively high excess diffusion barrier, Delta E-s = 0.13 eV, at the step edges. Several experimental methods have been developed to measure the step edge barrier in this system over a wide coverage range. The probability for an atom to move from a higher to a lower layer depends on both the barrier and the prefactor, so it is important to lest whether the prefactors for hopping over a step, v(s), and for hopping on a terrace, v(t), are different. We present the results from several experiments on Ag/Ag(lll) to conclude that v(s)/v(t) = 10(2.0+/-0.3).