Raymond Peter Scaringe

A Theoretical Technique for Layer Structure Prediction

A new technique for the prediction of molecular layer structures is described. The essential information required is the structure of the molecule. The method takes advantage of the fact that molecular assemblies can be described as close-packed. In effect, this allows an analysis of the 9-dimensional potential hypersurface to be performed by searching a 3-dimensional, close-packed subspace. Use is made of geometric concepts, construction techniques, potential energy functions, and data base analysis to arrive at a quantitative method. Predictions are in the form of an all-atom, atomic-scale description of the structure. The methodology and underlying theory are discussed in detail. Predictions for 12 compounds of known structure are presented and compared to the experimental results. Molecular displacements can usually be predicted to within a few tenths of an Angstrom and the molecular orientation to within about ten degrees. The results indicate that the method is capable of accurate predictions even for systems with relatively strong interlayer interactions.