remains on the outermost surface layer during the faceting transformation. Another type of massive reconstruction has been very recently found in STM and LEED experiment for Pd on Ta(111) system [@szuk02]. The reconstructed surface consists of $\{011\}$ facets which form large triangular pyramids. The third type of reconstructed structure, coexistence of small $\{011\}$ facets with large $\{211\}$ facets, has been observed [@mad99b] in Pd on W(111) for prolonged annealing time (for short annealing time only $\{211\}$ pyramids occurred). An important step in understanding the thermal stability of reconstructed surfaces was LEED experiment performed in high temperatures for Pd on Mo(111) by Song et al. [@song95]. They demonstrated existence of reversible phase transition between faceted $\{211\}$ and planar phases and they found that this transition has a large hysteresis, i.e., the transition temperature in cooling cycle ($T\approx 830$) is lower than that in the heating cycle ($T\approx 870$).

In theoretical studies of overlayer-induced faceting [@mad99b; @leung97; @leung98] the first principle method have been used to calculate the surface formation energy of fcc metals (Pd, Pt, Au, Ag, Cu) adsorbed on Mo and W. Results of these calculation performed for pseudomorphic adsorbate overlayer on (111), (211), and (011) flat surfaces show that 