2019_EJRNL_PP_XIAOGUANG_MA_1.pdf
Terbatas Ratnasari
» ITB
Terbatas Ratnasari
» ITB
We experimentally characterize heterogeneous nonexponential relaxation in bidisperse supercooled
colloidal liquids utilizing a recent concept called “softness” [Phys. Rev. Lett. 114, 108001 (2015)]. Particle
trajectory and structure data enable classification of particles into subgroups with different local
environments and propensities to hop. We determine residence times t R between particle hops and show that tR derived from particles in the same softness subgroup are exponentially distributed. Using the mean residence time ?tR for each softness subgroup, and a Kramers’ reaction rate model, we estimate the activation energy barriers E b for particle hops, and show that both ?tR and E b are monotonic functions of softness. Finally, we derive information about the combinations of large and small particle neighbors that determine particle softness, and we explicitly show that multiple exponential relaxation channels in the supercooled liquid give rise to its nonexponential behavior.