SHORT-WAVELENGTH ASYMPTOTICS OF TIME CORRELATION FUNCTIONS
Author(s): V.V.Ignatyuk (Institute for Condensed Matter Physics of the National Academy of Sciences of Ukraine, 1 Svientsitskii Str., 79011 Lviv, Ukraine)
Short-wavelength asymptotics of time correlation functions (TCF) of simple classical fluids is considered in the framework of short time expansion. The explicit expressions for zeroth time moments up to the 8-th order of cumulant are presented in the framework of additive approach. It is shown that unlike the dynamic structure factor which is found to have Gaussian form in short-wavelength limit, nongaussian corrections are present in TCF ``density-energy'' and ``energy-energy''. The comparison with generalized collective modes approach as well as data for quantum liquids is discussed.
Key words: time correlation functions, short-wavelength limit, generalized
collective modes, cumulant expansion
PACS: 05.70.Ln, 51.10.+y, 61.20.Lc, 61.20.Ne
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