Metal surfaces undergo structural change by the dissociative adsorption of O2, where the reconstructuring is caused by either of the two distinctive mechanisms depending on the temperature and/or the crystalographic planes, one is the “adsorption induced reconstruction” and the other is the “formation of quasi-compounds and their array over the surface”.

The oxygen induced reconstruction of Cu(100) is the former case. When a Cu(100) surface is exposed to O2, oxygen atoms are adsored by making nano-size c(2x2) structure to avoid the convergence of the stress induced by the adsorption. When the oxygen coverage exceeds a critical value of ca 0.3 ML, Cu atoms are missed from the substrate surface to release the stress and the R45 reconstruction is established. In contrast to the Cu(l00) surface, an entirely different process takes place on a Cu( 110) surface exposed to O2, where the (-Cu-O-) string is formed and by a chemical array over the terrace occur.