Molecular triangulation – finding the conformation of adsorbed self-assembled organic monolayers

We have developed a method that images two or more C–H bond directions within a complex adsorbed molecule on a single-crystal substrate. Since most surface-science methods are insensitive to H atoms in adsorbed molecules, this method offers unique capabilities for determining molecular conformations of relatively complex molecules at surfaces, permitting studies of structural changes over a wide range of coverage. This procedure, called molecular triangulation, is a new development based on the electron stimulated desorption ion angular distribution (ESDIAD) phenomenon used to measure individual bond directions in simple adsorbed molecules. The new ESD-molecular triangulation (ESD-MT) method provides incisive conformational information for large adsorbed organic species.