Time and length scales for diffusion in liquids.
The first six even moments of the displacement of a molecule in water and an atom in liquid argon are found by molecular dynamics simulations and compared with the moments predicted by diffusion theory. We find a noticeable difference between the moments higher than the second. The ratio between predicted and calculated moments approaches unity as 1/t for times larger than 10 ps. Continuous time random walk is used to explain this slow approach of the moments to their diffusion limit.
Center for Information Technology, National Institutes of Health, Bethesda, Maryland 20892, USA. berezh@speck.niddk.nih.gov
A M
AM
Berezhkovskii
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G
Sutmann
D001128:Argon / Q000737:chemistry; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D004058:Diffusion; D008956:Models, Chemical; D013816:Thermodynamics; D014867:Water / Q000737:chemistry
D014867:Water; D001128:Argon