Non-equilibrium dynamics of glass-forming liquid mixtures Article uri icon

abstract

  • The non-equilibrium self-consistent generalized Langevin equation theory of irreversible processes in glass-forming liquids [P. Ramírez- González and M. Medina-Noyola, Phys. Rev. E 82, 061503 (2010)] is extended here to multi-component systems. The resulting theory describes the statistical properties of the instantaneous local particle concentration profiles nα(r, t) of species α in terms of the coupled time-evolution equations for the mean value nα ( r,t) and for the covariance σαβ(r,r′;t)=δnα(r,t) δnβ(r′,t)̄ of the fluctuations δnα(r,t)= nα(r,t)-n̄α(r,t). As in the monocomponent case, these two coarse-grained equations involve a local mobility function b α(r, t) for each species, written in terms of the memory function of the two-time correlation function Cαβ(r,r′;t, t′)=δnα(r,t)δnβ(r′,t′)̄. If the system is constrained to remain spatially uniform and subjected to a non-equilibrium preparation protocol described by a given temperature and composition change program T(t) and n̄α(t), these equations predict the irreversible structural relaxation of the partial static structure factors Sαβ(k; t) and of the (collective and self) intermediate scattering functions Fαβ(k, τ; t) and FαβS(k,τ;t). We illustrate the applicability of the resulting theory with two examples involving simple model mixtures subjected to an instantaneous temperature quench: an electroneutral binary mixture of equally sized and oppositely charged hard-spheres, and a binary mixture of soft-spheres of moderate size-asymmetry. © 2014 AIP Publishing LLC.

publication date

  • 2014-01-01