  An earlier model for substrate strain mediated interactions between monomer
adatoms is extended to the interaction of monomers with dimers and the
interaction of dimers. While monomers (sitting on high symmetric sites) are
supposed to create isotropic stress on the substrate, dimers would create
anisotropic stress caused by stretching their bond. Resulting interactions are
strongly angle dependent and also reflect the elastic anisotropy of the
substrate. The applicability of a continuum elastic model and its limitations
are discussed. Consequences for modelling adatom structures are sketched
without detailed analysis.

Materials Science