Molecular dynamics analyzed in terms of continuous measures of dynamic heterogeneity

We analyse the relaxation data of a supercooled liquid in terms of φ(t) = ∫ g(ln τ) φ(t/τ) d ln τ using a Kohlrausch, Williams, and Watts (KWW) type integral kernel φ(t/τ) with exponent, β_hom, which serves for varying the degree of homogeneity inherent in the response of each relaxor, while the concomitant g(ln τ) defines the extent of dynamic heterogeneity. The simulated time dependence of solvation free energies as a function of β_h0m is compared with experimental solvation dynamics data, ν(t) and σ_inh(t) derived from time resolved inhomogeneously broadened optical lineshapes. The experimental findings indicate 0.8 ≤ β_hom ≤ 1, which states that the dynamical nature of the relaxation process is dominated by the spatial variation of relaxation times, while the possible extent of homogeneous dispersion remains small.