Intermolecular momentum transfer in a simple liquid and its contribution to shear viscosity

Momentum transfer in a sheared liquid is analyzed with a focus on the inter molecular momentum transfer (IMT). The IMT, which determines shear viscosit y of liquids, is examined based on the result of molecular dynamics (MD) si mulations for a simple liquid modeled by the Lennard-Jones (12-6) potential . Distortion of liquid structure, which is characterized by spherical symme try breaking in the pair distribution of molecules, is reproduced by the MD simulation and its effect on the characteristics of the IMT, which include s a negative momentum transfer in a certain range of intermolecular distanc e, is discussed. The appearance of negative IMT depends on characteristics of the intermolecular potential, and it is predicted that the IMT will show a different response for repulsive soft-sphere liquids.