Hydrodynamic theory for vibrational dephasing in liquids

A hydrodynamic model is presented for the dephasing of molecular vibrations in liquids; the effects of vibrational anharmonicity are included. Agreement with coherent picosecond pulse experiments and isotropic Raman line shape data is good for lower viscosity liquids, and the qualitative temperature and density dependence of the dephasing rate is predicted correctly. The final result shows a surprising formal similarity to the isolated binary collision model developed previously.