The group theory of shear induced pair radial distribution functions in atomic liquids

Abstract

Angular resolution of the pair radial distribution function in computer simulations of shear induced thickenening in atomic (Lennard-Jones) liquids has revealed the presence of anisotropic local structure which is explained on the basis of group theoretical statistical mechanics. This explains the observed structural asymmetry from the basic assumption that the symmetry of allowed ensemble averages in the steady state in the presence of shear is the same as that of the applied strain rate. The computer simulation results are reproduced from group theory by assuming that the crystal like lattice arrangement of atoms which appear in the simulations under shear can be described by some of the thirty two crystallographic point groups, namely hexagonal, trigonal, and triclinic. The hexagonal lattice symmetries C3h and C6h; the trigonal symmetry S6; and the triclinic symmetry Ci(S2) are found to support the crystal-like structures necessary to explain the observed angular resolution of the pair radial distribution function.