Equilibration and Aging of Liquids of Non-Spherically Interacting Particles

The nonequilibrium self-consistent generalized Langevin equation theory of irreversible processes in liquids is extended to describe the positional and orientational thermal fluctuations of the instantaneous local concentration profile n(r,Ω,t) of a suddenly quenched colloidal liquid of particles interacting through nonspherically symmetric pairwise interactions, whose mean value n(r,Ω,t) is constrained to remain uniform and isotropic, n (r,Ω, t) = n (t). Such self-consistent theory is cast in terms of the time-evolution equation of the covariance [Formula: see text] of the fluctuations [Formula: see text] of the spherical harmonics projections nlm(k;t) of the Fourier transform of n(r,Ω,t). The resulting theory describes the nonequilibrium evolution after a sudden temperature quench of both, the static structure factor projections Slm(k,t) and the two-time correlation function [Formula: see text], where τ is the correlation delay time and t is the evolution or waiting time after the quench. As a concrete and illustrative application we use the resulting self-consistent equations to describe the irreversible processes of equilibration or aging of the orientational degrees of freedom of a system of strongly interacting classical dipoles with quenched positional disorder.