HYDRODYNAMICS OF 2-DIMENSIONAL SMECTICS ON FLUID SURFACES

The long wavelength hydrodynamics of films with unidirectional translational order adsorbed on fluid surfaces (as in a Langmuir monolayer) is formulated. We find the hydrodynamic frequencies omega(q) is-proportional-to (+/- square-root 3-i)q 14/9cos4/3theta sin14/9theta where q= Absolute value of q and pi/2-theta is the angle between the direction of propagation and the direction of translational order. We also obtain the dynamic structure factor. Our results apply to nematic polymers adsorbed onto a fluid surface and to striped phases of Langmuir monolayers, and provide an experimentally accessible probe of the anomalous elasticity predicted for two-dimensional smectics by Golubovic and Wang.