Atomic mechanism of flow in simple liquids under shear.

Atomic correlations in a simple liquid in steady-state flow under shear stress are studied by molecular dynamics simulation. The local atomic level strain is determined through the anisotropic pair-density function. The atomic level strain has a limited spatial extension whose range is dependent on the strain rate and extrapolates to zero at the critical strain rate. A failure event is identified with altering the local topology of atomic connectivity by exchanging bonds among neighboring atoms.