We have developed a method of calculating the epitaxial energy for the
systems with addictive/nonaddictive potentials. This method is applie
d to fcc(111)/bcc(110) system and Au (001) surface reconstruction. We
find that five different epitaxial modes of the fcc(111)/bcc(110) syst
ems may be observable in an experiment. The topmost layer of the Au(00
1) surface is reconstructed to a contracted hexagonal face. The contra
ction ratio with respect to the unreconstructed Au(111)surface is abou
t 3.5%. For the first time in the literature, we predict theoretically
that the in-plane epitaxial orientation of the reconstructed layer is
0 degrees and 0.7 degrees depending on the cluster size. The hexagona
l layer is slightly distorted and buckled. These findings are in very
good agreement with experiental results.