کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
977891 | 933220 | 2008 | 9 صفحه PDF | دانلود رایگان |
![عکس صفحه اول مقاله: A statistical-mechanical theory of self-diffusion in glass-forming liquids A statistical-mechanical theory of self-diffusion in glass-forming liquids](/preview/png/977891.png)
A statistical-mechanical theory of self-diffusion in glass-forming liquids is presented. A non-Markov linear Langevin equation is derived from a Newton equation by employing the Tokuyama–Mori projection operator method. The memory function is explicitly written in terms of the force-force correlation functions. The equations for the mean-square displacement, the mean-fourth displacement, and the non-Gaussian parameter are then formally derived. The present theory is applied to the glass transitions in the glass-forming liquids to discuss the crossover phenomena in the dynamics of a single particle from a short-time ballistic motion to a long-time self-diffusion process via a ββ (caging) stage. The effects of the renormalized friction coefficient on self-diffusion are thus explored with the aid of analyses of the simulation results by the mean-field theory proposed recently by the present author. It is thus shown that the relaxation time of the renormalized memory function is given by the ββ-relaxation time. It is also shown that for times longer than the ββ-relaxation time the dynamics of a single particle is identical to that discussed in the suspensions.
Journal: Physica A: Statistical Mechanics and its Applications - Volume 387, Issue 21, 1 September 2008, Pages 5003–5011