Eur. Phys. J. B 82, 271-293 (2011)
https://doi.org/10.1140/epjb/e2011-20075-4

Time scale bridging in atomistic simulation of slow dynamics: viscous relaxation and defect activation

¹ Department of Nuclear Science and Engineering, Massachusetts Institute of Technology, Cambridge, 02139 Massachusetts, USA
² Department of Materials Science and Engineering, University of Pennsylvania, Philadelphia, 19104 Pennsylvania, USA
³ Department of Nuclear Engineering, North Carolina State University, Raleigh, 27695 NC, USA
⁴ Center for Advanced Modeling and Simulation, Idaho National Laboratory, Idaho Falls, 83415 ID, USA
⁵ Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, 02139 Massachusetts, USA
⁶ Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, 30332 GA, USA

Corresponding author: ^a jacob.eapen@ncsu.edu

Received: 28 January 2011
Revised: 15 June 2011
Published online: 17 August 2011

Abstract

Atomistic simulation methods are known for timescale limitations in resolving slow dynamical processes. Two well-known scenarios of slow dynamics are viscous relaxation in supercooled liquids and creep deformation in stressed solids. In both phenomena the challenge to theory and simulation is to sample the transition state pathways efficiently and follow the dynamical processes on long timescales. We present a perspective based on the biased molecular simulation methods such as metadynamics, autonomous basin climbing (ABC), strain-boost and adaptive boost simulations. Such algorithms can enable an atomic-level explanation of the temperature variation of the shear viscosity of glassy liquids, and the relaxation behavior in solids undergoing creep deformation. By discussing the dynamics of slow relaxation in two quite different areas of condensed matter science, we hope to draw attention to other complex problems where anthropological or geological-scale time behavior can be simulated at atomic resolution and understood in terms of micro-scale processes of molecular rearrangements and collective interactions. As examples of a class of phenomena that can be broadly classified as materials ageing, we point to stress corrosion cracking and cement setting as opportunities for atomistic modeling and simulations.