Classification of continuous order-disorder transitions in adsorbed monolayers. II

Abstract

We extend the classification of continuous order-disorder transitions in adsorbed systems to encompass additional situations of physical interest. Among these are transitions on substrate arrays which are not simple Bravais lattices. The honeycomb and kagomé lattices are treated in detail. Their transitions belong to the universality class of the Ising, three- or four-state Potts model, and the Heisenberg model with cubic anisotropy. A simple case of the transitions of diatomic molecules is also considered. Those of ${\mathrm{Br}}_2$ on graphite are predicted to be first order. Lastly, transitions between ordered states are analyzed and an example of experimental interest is discussed.