Emergence of cooperatively reorganizing cluster and super-Arrhenius dynamics of fragile supercooled liquids.

摘要: In this paper, we develop a theory to calculate the structural relaxation time ${\ensuremath{\tau}}_{\ensuremath{\alpha}}$ of fragile supercooled liquids. Using information configurational entropy and structure, number dynamically free, metastable, stable neighbors around central particle. liquids, cooperatively reorganizing clusters (CRCs) in which form ``stable'' nonchemical bonds with particle emerge. For an event take place, these have reorganize irreversibly; energy involved processes is effective activation relaxation. The brings forth temperature ${T}_{a}$ temperature-dependent parameter $\ensuremath{\psi}(T)$ characterize slowing down dynamics on cooling. It shown that value equal 1 for $Tg{T}_{a},$ indicating underlying microscopic mechanism dominated by entropy-driven processes, while $Tl{T}_{a},$ decreases cooling, emergence energy-driven processes. This crossover from high low temperatures explains seen ${\ensuremath{\tau}}_{\ensuremath{\alpha}}$. systems may similar static structure but very different can be understood terms $\ensuremath{\psi}(T)$. We present results Kob-Anderson model three densities show calculated values are excellent agreement simulation all densities. also when $\ensuremath{\psi}(T),$ ${\ensuremath{\tau}}_{\ensuremath{\alpha}},$ other quantities plotted as function $T/{T}_{a}$ $(\mathrm{or} {T}_{a}/T)$, data collapse master curves.