Erratum

We describe a simple method to generate a number of plausible trial structures for layers of chemisorbed molecules on metal surfaces, based on symmetry arguments. The formation, or packing, energy of these layers can be evaluated as sums of non-bonded interactions, and their stability can be judged on the basis of the shape of the packing energy profile as a function of molecular rotation. For naphthalene and azulene on Rh(111), p3 and pgg (or pg) structures are found to be the most stable. The definition and possible appearance of “twinned” layer structures is discussed. The method is claimed to provide inexpensive and reliable structural information for layers of large covalent molecules.