Theoretical approach of the infrared profile of molecular adsorbates on clean surfaces: inhomogeneous broadening Original Research Article

A simple analytical approach is developed to interpret the infrared profile of molecules adsorbed on surfaces without defects. The homogeneous profile is convoluted by a potential distribution function which describes the radial and orientational arrangement of mutually interacting admolecules on the surface. The resulting profile shape is thus asymmetric and its behavior is discussed in terms of a reduced set of interaction potential coefficients and physical parameters (temperature and coverage). Although the model is simple since it is based on a simplified expression of the binding and lateral interactions for the adsorbate–substrate system, it gives the main trends of the profile shape behavior for CO and NH3 adsorbed on ionic substrates.