Program

O.3 -- Oral, NCTP-40

Date: Monday, 27 July 2015

Time: 11h40 - 12h00

The study of dynamics heterogeneity and slow down of network-forming liquid computer simulation

P. K. Hùng (1), L. T. San (1), H. V. Huệ (2)

(1) Hà Nội University of Sicience and Technology (2) Tay Nguyen University

We have numerically studied the diffusion in silica liquid following an approach that the particles mobility is evaluated via the SiOx SiOx 1 and and OSiy OSiy 1 reactions. Four models at temperatures from 2600 to 3500 K have been constructed by molecular dynamic simulation. The simulation reveals that the liquid has a tetrahedral network structure with a small amount of defect-cells. Moreover, defect-cells do not uniformly distribute in the liquid, but they have a tendency to form clusters. Further, we found two distinct clusters. First cluster contains the particles on which no reaction happens. The second cluster consists of particles where the reactions frequently happen. The mobility of atoms in the none-reaction cluster is significantly smaller than in the reaction cluster. This clearly indicates the coexistence of slow and fast mobility regions. The size of two mention clusters strongly depends on the temperature. The dynamics slowdown near glass transition point is interpreted by the percolation of none-reaction cluster.

Presenter: Phạm Khắc Hùng