The Short-Time Dynamics of a Test Particle in a Dense Fluid

Wo-Kyung Sung ； H. L. Friedman

《Chinese Journal of Physics》 28卷1期 (1990/02) Pp. 37-48

並列摘要

A useful means of probing the dynamic interaction between a particle and the background in liquid is the measurement of Hall effect. According to the theory, the Hall effect is given in terms of the off-diagnoal momentum time correlation function ＜px(t)py(0) ＞ with a magnetic field along z-axis. We have developed a theory for the time correlation function on the basis of the projection operator formalism of Mori and Zwanzig. Our theory for a simple liquid shows that the Hall number h is given as h = 1-K(D^(-1)-DE^(-1) )^2 . Here K is a positive number depending on the density, D is the self-diffusivity of particle, DE is its Enskog-theory approximation. The deviation of h from unity is a remarkable outcome of the collective dynamics involving more than two particles which happens at such a time as short as several collision times. This prediction is in agreement with the results of molecular dynamics simulation on a model system of hard-spheres.