Investigation of the Rayleigh critical angle phenomenon for the characterization of surface properties

Rayleigh critical angle experiments (on a water-solid interface) have been performed on samples ranging from single crystals to polycrystalline alloys and glasses. Two basic conclusions can be drawn from this work: (1) linear equations of motion (which include anisotropy) suffice for an approximate description of the observations, including the calculation of critical angles from second order elastic constants; and (2) at and near the Rayleigh critical angle, anomalous production of harmonics is observed.