Molecular phase space transport in water: non-stationary random walk model

Dmitry Nerukh, Vladimir Ryabov, Makoto Taiji

    Research output: Contribution to journalArticlepeer-review


    Molecular transport in phase space is crucial for chemical reactions because it defines how pre-reactive molecular configurations are found during the time evolution of the system. Using Molecular Dynamics (MD) simulated atomistic trajectories we test the assumption of the normal diffusion in the phase space for bulk water at ambient conditions by checking the equivalence of the transport to the random walk model. Contrary to common expectations we have found that some statistical features of the transport in the phase space differ from those of the normal diffusion models. This implies a non-random character of the path search process by the reacting complexes in water solutions. Our further numerical experiments show that a significant long period of non-stationarity in the transition probabilities of the segments of molecular trajectories can account for the observed non-uniform filling of the phase space. Surprisingly, the characteristic periods in the model non-stationarity constitute hundreds of nanoseconds, that is much longer time scales compared to typical lifetime of known liquid water molecular structures (several picoseconds).
    Original languageEnglish
    Pages (from-to)4719-4726
    Number of pages8
    JournalPhysica A
    Issue number22
    Early online date5 Aug 2009
    Publication statusPublished - 15 Nov 2009

    Bibliographical note

    NOTICE: this is the author’s version of a work that was accepted for publication in <Journal title>. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Nerukh, D, Ryabov, V & Taiji, M 2009, 'Molecular phase space transport in water: hon-stationary random walk model', Physica a: statistical mechanics and its applications , vol 388, no. 22, (2009) DOI


    • phase space transport
    • statistical complexity
    • computational mechanics
    • symbolic dynamics
    • non-stationary diffusion
    • random walk
    • liquid water


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