Søren L Frederiksen

Publications (2)7.37 Total impact

• Source

  Available from: cornell.edu

  Article: Bayesian ensemble approach to error estimation of interatomic potentials.

  Søren L Frederiksen, Karsten W Jacobsen, Kevin S Brown, James P Sethna
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  ABSTRACT: Using a Bayesian approach a general method is developed to assess error bars on predictions made by models fitted to data. The error bars are estimated from fluctuations in ensembles of models sampling the model-parameter space with a probability density set by the minimum cost. The method is applied to the development of interatomic potentials for molybdenum using various potential forms and databases based on atomic forces. The calculated error bars on elastic constants, gamma-surface energies, structural energies, and dislocation properties are shown to provide realistic estimates of the actual errors for the potentials.
  Physical Review Letters 11/2004; 93(16):165501. · 7.37 Impact Factor
• Article: Simulations of intergranular fracture in nanocrystalline molybdenum

  Søren L. Frederiksen, Karsten W. Jacobsen, Jakob Schiøtz
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  ABSTRACT: Using molecular dynamics simulations we investigate the plastic deformation of nanocrystalline molybdenum with a grain size of 12 nm at high strain rates. The simulations are performed with an interatomic potential which is obtained through matching of atomic forces to a database generated with density-functional calculations. The simulations show the plastic deformation to involve both grain boundary processes and dislocation migration which in some cases lead to twin boundary formation. A large component of the strain is accommodated through the formation of cracks in the grain boundaries. This behavior is very different from what has been seen earlier in simulations of fcc metals where grain boundary sliding is the dominant mechanism for very small grain sizes.
  Acta Materialia.