Monomer adsorption on equilateral triangular lattices with attractive first-neighbor interactions.

We have recently studied a model of monomer adsorption on infinitely long equilateral triangular lattices with terraces of finite width M and nonperiodic boundaries. This study was restricted to the case of repulsive adsorbate-adsorbate first-neighbor interactions but included attractive, repulsive, and negligible second-neighbor interactions. The present work extends this study to the case of attractive first-neighbors, and the phases are determined, as before, with a confidence exceeding 10 significant figures. Phase diagrams are included for terrace widths M < or =11. Most of the occupational characteristics of the phases fit exact analytic expressions in M. The infinite-M limit of these expressions, combined with other analyses, provide the complete phase diagram for the infinite two-dimensional lattice. In addition to the empty and full coverage phases, there are three phases exhibiting stripe and cluster features that were not observed in the case of repulsive first-neighbors.