Kinetic theory of density fluctuations in one component monatomic fluids at equilibrium

Joyce Noah, Stanford University

A diagrammatic formulation of the kinetic theory of density fluctuations in equilibrium classical fluids is used to investigate the behavior of the time correlation function. The kinetic theory of fluctuations is important for the reason that transport coefficients can be expressed in terms of time correlation functions. Furthermore, neutron scattering and light scattering experiments can also be expressed in terms of time correlation functions.

The system of interest is a monatomic classical fluid with strongly repulsive forces and weaker attractive forces. Using the diagrammatic kinetic theory, the correlation function and the memory function can be expressed as an infinite series of diagrams. The binary collision approximation to the memory function is an infinite subset of these diagrams that represent the physics of two particle collisions.

The matrix elements of the memory function in the binary collision approximation are evaluated using two particle trajectory calculations. The matrix elements are used to calculate the correlation function. The calculated correlation functions are then compared to correlation functions obtained from molecular dynamics simulations to determine the accuracy of the approximation.

Abstract Author(s): Joyce E. Noah<br />Advisor: Hans C. Andersen