Equilibration and Aging of Liquids of Non-Spherically Interacting Particles Article uri icon

abstract

  • 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,-,t) of a suddenly quenched colloidal liquid of particles interacting through nonspherically symmetric pairwise interactions, whose mean value n(r,-,t) is constrained to remain uniform and isotropic, n (r,-, t) = n (t). Such self-consistent theory is cast in terms of the time-evolution equation of the covariance σ(t)=δnlm(k;t)δnlm†(k;t)ō of the fluctuations δnlm(k;t)=nlm(k;t)nlmō(k;t) of the spherical harmonics projections nlm(k;t) of the Fourier transform of n(r,-,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 Flm(k,τ;t)≥δnlm(k,t)δnlm(k,t%2bτ)ō, 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. © 2016 American Chemical Society.

publication date

  • 2016-01-01