The dynamic properties of iron liquid (Fe) are studied by molecular dynamics (MD) simulation. We trace the evolution of local density fluctuations (LDFs) in Fe liquid over the simulation time and in the 300-2300 K temperature range. The result simulation reveals that atomic diffusion is realized through the LDFs and the high localization LDFs at low temperature in the iron liquid is the cause of the anomalous dynamics slowdown. We find that the diffusion depends on both rate of LDFs and the averaged square displacement of particles Fe as one LDF occurs. As the temperature decreases, both quantities reduce. | Nguyễn Thị Thanh Hà và Đtg Tạp chí KHOA HỌC & CÔNG NGHỆ 135(05): 167 - 172 STUDYING DIFFUSION MECHANISM AND DYNAMICS SLOWDOWN IN IRON LIQUID Nguyen Thi Thanh Ha*, Le Van Vinh, Pham Khac Hung Hanoi University of Science and Technology SUMMARY The dynamic properties of iron liquid (Fe) are studied by molecular dynamics (MD) simulation. We trace the evolution of local density fluctuations (LDFs) in Fe liquid over the simulation time and in the 300-2300 K temperature range. The result simulation reveals that atomic diffusion is realized through the LDFs and the high localization LDFs at low temperature in the iron liquid is the cause of the anomalous dynamics slowdown. We find that the diffusion depends on both rate of LDFs and the averaged square displacement of particles Fe as one LDF occurs. As the temperature decreases, both quantities reduce. Keywords: Molecular dynamics simulation, iron liquid, dynamics slowdown, diffusion, local density fluctuations. INTRODUCTION* This transition to a disordered solid known as the glass transition is accompanied with the drastic increase in the viscosity and a subtle change in the structure. Understanding the microscopic mechanism governing glass transitions is one of the most important problems in statistical physics [1-3]. To tackle this problem, several working hypotheses have been proposed. The studies from refs.[48] focus on the dynamics heterogeneity, the percolation in real space and properties of energy landscapes. They found the existence of mobile and immobile regions which migrate in the space over time. Authors in [910] put forward the mechanism by which the small modification of statistic density correlations can produce an extremely large dynamical change. The essential result in this direction is the mode coupling theory [9] that predicts a freezing of dynamics from the nonlinear feedback effect. The theoretical and experimental investigations on universal mechanisms controlling slow dynamics have been done .
