This title appears in the Scientific Report :
2017
Please use the identifier:
http://hdl.handle.net/2128/16221 in citations.
Biasing Technique in Parallel Monte Carlo Simulations for Segregation in Solids
Biasing Technique in Parallel Monte Carlo Simulations for Segregation in Solids
The modeling of segregation at low temperature is challenging due to the strong time scale ofthe Molecular Dynamics simulations. In order to solve Newton's equations of motion, the timestep of the simulation is of the order of femtoseconds. However, diusion occurs after severalseconds, or hours...
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Personal Name(s): | Longsworth, Margarita (Corresponding author) |
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Contributing Institute: |
Jülich Supercomputing Center; JSC |
Imprint: |
2017
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Physical Description: |
105 pp. |
Dissertation Note: |
Masterarbeit, RWTH Aachen, 2017 |
Document Type: |
Master Thesis |
Research Program: |
Computational Science and Mathematical Methods |
Link: |
OpenAccess OpenAccess |
Publikationsportal JuSER |
The modeling of segregation at low temperature is challenging due to the strong time scale ofthe Molecular Dynamics simulations. In order to solve Newton's equations of motion, the timestep of the simulation is of the order of femtoseconds. However, diusion occurs after severalseconds, or hours, depending on the described system. The Particle-Exchange Monte CarloMethod, combined Molecular Dynamics and Monte Carlo Techniques to model solute diusionin crystals. In this work, the simulation of a Cottrel Atmosphere formed by Carbon atomsaround a screw dislocation in an iron matrix at T=0K is optimized. Inecient sampling of theconguration space lead to slow convergence of the simulations. Therefore, a model systemof the complex atomistic system is used to test a biasing rule on the selection probability oftrial moves. The purpose of doing this is to explore the possibility to enhance sampling inregions where more successful trial moves occurred using an appropriate selection rule. Thesimulation time in the model system was much less demanding than in the atomistic system,which allowed us to perform more experiments. The biasing parameters were tested andgauged to speed-up the simulation in the atomistic system. The simulation was drasticallysped up in all cases. The results in the carbon conguration displayed the three-fold symmetryof the screw dislocation, which validates the obtained results. |