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We have analyzed the asymmetry between growth and dissolution using Monte Carlo simulations of flat and vicinal (100) surfaces of a Kossel crystal. We find that at a high driving force dissolution is very anisotropic and nearly atomically flat surfaces are produced, if the nearest-neighbor bond strength is sufficiently large. This effect we call kinetic smoothing. For wet-chemical etching of the Si(111) surface, the chemical-etch reaction determines the annihilation rate constants. If the differences between the rate constants for removal of atoms from kink, step, and terrace sites are large enough, then we observe smooth surfaces and anisotropic etching, i.e., kinetic smoothing. If etching is anisotropic, knowledge of the annihilation rate constants suffices to find an analytical expression for the etch rate as a function of misorientation. This expression can be used to fit experimental etch rates for etching of vicinal Si(111) in potassium hydroxide.

The atomistic mechanisms and dynamics of the (1 x 1) --> hex surface reconstruction of the clean Pt(100) and its lifting upon CO adsorption have been studied by means of both density functional theory and molecular dynamics simulations based on the modified embedded-atom method. It was found that during the surface reconstruction from the square (1 x 1) to the approximately 20% more dense (quasi)hexagonal phase, the required extra atoms are extracted from the second layer, leaving highly mobile subsurface vacancies, even in the presence of adatom islands or steps. These vacancies will, by surface diffusion, coalesce to form steps. In contrast, during the reverse process--where the hex surface reconstruction is lifted upon adsorption of CO--the roughly 20% excess surface atoms are in a collective manner ejected to form chains of adatoms. In turn, these adatoms coalesce into islands and steps by surface diffusion. A result of the two totally different mechanisms is that the reconstruction process can be concluded not to be the reverse of the deconstruction process.

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