The shoving model for the glass-former LiCl·6H2O: A molecular dynamics simulation study

Molecular dynamics (MD) simulations of LiCl·6H2O showed that the diffusion coefficient D, and also the structural relaxation time <τ>, follow a power law at high temperatures, D−1 ∝ (T − To)−μ, with the same experimental parameters for viscosity (To = 207 K, μ = 2.08). Decoupling between D and <τ> occurs at Tx ∼ 1.1To. High frequency acoustic excitations for the LiCl·6H2O model were obtained by the calculation of time correlation functions of mass current fluctuations. The temperature dependence of the instantaneous shear modulus, G∞(T), was considered in the shoving model for supercooled liquids [J.C. Dyre, T. Christensen, N.B. Olsen, J. Non-Cryst. Solids 352 (2006) 4635] resulting in a linear relationship log (D−1) vs. G∞/T.