Abstract
Several molecular dynamics experiments in monoatomic fluids indicate that the velocity v of a tagged particle has a clear non-Gaussian behaviour: here we present typical simulation data obtained for <v 2(0)v 2(t)>. We have previously found that at long times these non-Gaussian features can be explained in terms of a non-linear Langevin equation developed by Mori, Fujisaka and Shigematsu. Here we show that the latter approach can be the long-time version of the reduced model known as the non-linear itinerant oscillator. In principle, such a model can also reproduce the non-Gaussian behaviour at short times, as found in the simulations and confirmed by the proper sum rules. The reduced model is numerically solved in a particular one-dimensional overdamped case and the main features present in the computer experiment are found to be qualitatively reproduced.
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References
Grigolini, P.: Chem. Phys.38, 389 (1979)
Evans, M.W., Evans, G.J., Coffey, W.T., Grigolini, P.: Molecular dynamics. Chap. 9 and 10. John Wiley 1982
Grigolini, P.: Nuovo Cimento63B, 174 (1981)
Zwanzig, R.: Lectures in theoretical physics. (Boulder) Vol. 3, p. 106. New York, 1960
Mori, H.: Prog, Theor. Phys.33, 423 (1965);34, 399 (1965)
Mori, H., Fujisaka, H., Shigematsu, H.: Prog. Theor. Phys.51, 109 (1974)
Ferrario, M., Grigolini, P.: J. Math. Phys.20, 2567 (1979)
Boon, J.P., Yip, S.: Molecular hydrodynamics. New York: Mac Graw Hill 1980
Grigolini, P.: Chem. Phys. Lett.47, 483 (1977)
Grigolini, P., Lami, A.: Chem. Phys.30, 61 (1978)
Balucani, U., Tognetti, V., Vallauri, R., Grigolini, P., Lombardo, M.P.: Phys. Lett.86A, 426 (1981)
Giordano, M., Grigolini, P., Marin, P.: Chem. Phys. Lett.83, 554 (1981)
Weeks, J.D., Chandler, D., Andersen, H.C.: J. Chem. Phys.54, 5237 (1971)
Berne, B.J., Boon, J.P., Rice, S.A.: J. Chem. Phys.45, 1086 (1966)
Nordholm, S., Zwanzig, R.: J. Stat. Phys.13, 3471 (1975)
Prestgard, E., Kampen, N.G. van: Mol. Phys.43, 33 (1981)
Ferrario, M., Evans, M.W., Coffey, W.T.: Private communication
Vollmer, H.D., Risken, H.: Physica110A, 106 (1982)
Titulaer, U.M.: Physica91A, 321 (1978)
Grigolini, P.: J. Stat. Phys.27, 283 (1982)
Haken, H.: Synergetics. Berlin, Heidelberg, New York: Springer-Verlag 1977
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Balucani, U., Tognetti, V., Vallauri, R. et al. Non-gaussian velocity correlations in fluids. Z. Physik B - Condensed Matter 49, 181–190 (1982). https://doi.org/10.1007/BF01313025
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DOI: https://doi.org/10.1007/BF01313025