The Potential Energy Landscape and Mechanisms of Diffusion in Liquids
arXiv:cond-mat/0109154 · doi:10.1103/PhysRevE.65.041106
Abstract
The mechanism of diffusion in supercooled liquids is investigated from the potential energy landscape point of view, with emphasis on the crossover from high- to low-T dynamics. Molecular dynamics simulations with a time dependent mapping to the associated local mininum or inherent structure (IS) are performed on unit-density Lennard-Jones (LJ). New dynamical quantities introduced include r2_{is}(t), the mean-square displacement (MSD) within a basin of attraction of an IS, R2(t), the MSD of the IS itself, and g_{loc}(t) the mean waiting time in a cooperative region. At intermediate T, r2_{is}(t) posesses an interval of linear t-dependence allowing calculation of an intrabasin diffusion constant D_{is}. Near T_{c} diffusion is intrabasin dominated with D = D_{is}. Below T_{c} the local waiting time tau_{loc} exceeds the time, tau_{pl}, needed for the system to explore the basin, indicating the action of barriers. The distinction between motion among the IS below T_{c} and saddle, or border dynamics above T_{c} is discussed.
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References in corpus (6)
- Saddles in the energy landscape probed by supercooled liquids
- Phase space geometry and slow dynamics
- Instantaneous Normal Mode Analysis of Supercooled Water
- Fragile vs strong liquids: a saddles ruled scenario
- Role of the unstable directions in the equilibrium and aging dynamics of supercooled liquids
- Inherent-Structure Dynamics and Diffusion in Liquids
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