Binary collision approximations for the memory function for density fluctuations in equilibrium atomic fluids

PHYS 427

Joyce E. Noah, jnoah@stanford.edu and Hans C. Andersen, hca@stanford.edu. Department of Chemistry, Stanford University, Stanford, CA 94305
The kinetic theory of liquids provides a relationship between the time correlation function for density fluctuations and its memory function. Using a diagrammatic formulation of the kinetic theory of fluctuations in equilibrium liquids, we develop a series of binary collision approximations for the collisional part of the memory function. These approximations assume that the dynamics in a fluid consist of a sequence of uncorrelated binary collisions with either purely repuslive interactions (R); repulsive and attractive interactions (RA); or repulsive and attractive interactions with the effect of the surroundings taken into account (RAS). Comparing theoretical time correlation function results with those generated from molecular dynamics simulations reveals that the short time part of the RAS approximation yields the most quantitatively accurate results.
 

Poster Session
7:30 PM-10:00 PM, Wednesday, 13 September 2006 Moscone Center -- Hall D, Poster

Sci-Mix
8:00 PM-10:00 PM, Monday, 11 September 2006 Moscone Center -- Hall D, Sci-Mix

Division of Physical Chemistry

The 232nd ACS National Meeting, San Francisco, CA, September 10-14, 2006