Forces due to dynamic structure in thin liquid films

The long-range surface forces arising due to dynamic structure in thin liquid films are considered. The phonon formalism is applied to analyse the contribution of the collective motions in liquid to the excess free energy and the disjoining pressure of the film. It is shown that both the intermolecular interactions and the interactions between liquid and confining phases essentially have an influence on the sign and the magnitude of the phonon component of disjoining pressure and its temperature dependence. The methods and procedures used to assess the density of vibrational states for real and model liquids are discussed. The description of several spectroscopic experimental methodics specific for investigation of thin liquid interlayers is given concurrently with experimental data revealing the dynamic structuring in the course of film thinning.