The smoothing of artificial grooves on a high-symmetry crystal surface
below its roughening transition is investigated in the light of a one
-dimensional model. In the case of diffusion dynamics, a new, kinetic,
attractive interaction between steps opposes the contact repulsion an
d tends to flatten the top and the bottom of the profile in the transi
ent state anterior to complete smoothing. This phenomenon, which is ab
sent from continuum models, is weaker, but still present in real, two-
dimensional surfaces. Kinetic Monte Carlo simulations have been perfor
med for large modulation amplitudes in contrast with previous works. T
he relaxation time tau scales with the wavelength lambda as tau propor
tional to lambda(3) for diffusion dynamics and as tau proportional to
lambda(2) for evaporation dynamics. In the case of evaporation dynamic
s, the transient profile is sinusoidal. In the case of surface diffusi
on the profile presents blunted parts at the top and at the bottom, wh
ich result from the kinetic attraction between steps.