Coarse-grained molecular dynamics: Nonlinear finite elements and finite temperature Metadata

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Title

  • Main Title Coarse-grained molecular dynamics: Nonlinear finite elements and finite temperature

Creator

  • Author: Rudd, R E
    Creator Type: Personal
  • Author: Broughton, J Q
    Creator Type: Personal

Contributor

  • Sponsor: United States. Department of Energy.
    Contributor Type: Organization

Publisher

  • Name: Lawrence Livermore National Laboratory
    Place of Publication: Livermore, California
    Additional Info: Lawrence Livermore National Laboratory (LLNL), Livermore, CA

Date

  • Creation: 2005-05-30

Language

  • English

Description

  • Content Description: Coarse-grained molecular dynamics (CGMD) is a technique developed as a concurrent multiscale model that couples conventional molecular dynamics (MD) to a more coarse-grained description of the periphery. The coarse-grained regions are modeled on a mesh in a formulation that generalizes conventional finite element modeling (FEM) of continuum elasticity. CGMD is derived solely from the MD model, however, and has no continuum parameters. As a result, it provides a coupling that is smooth and provides control of errors that arise at the coupling between the atomistic and coarse-grained regions. In this article, we elaborate on the formulation of CGMD, describing in detail how CGMD is applied to anharmonic solids and finite temperature simulations. As tests of CGMD, we present in detail the calculation of the phonon spectra for solid argon and tantalum in 3D, demonstrating how CGMD provides a better description of the elastic waves than that provided by FEM. We also present elastic wave scattering calculations that show the elastic wave scattering is more benign in CGMD than FEM. We also discuss the dependence of scattering on the properties of the mesh. We introduce a rigid approximation to CGMD that eliminates internal relaxation, similar to the Quasicontinuum technique, and compare it to the full CGMD.
  • Physical Description: PDF-file: 35 pages; size: 0.7 Mbytes

Subject

  • Keyword: Spectra
  • STI Subject Categories: 75 Condensed Matter Physics, Superconductivity And Superfluidity
  • Keyword: Phonons
  • STI Subject Categories: 36 Materials Science
  • Keyword: Elasticity
  • Keyword: Simulation
  • Keyword: Argon
  • Keyword: Tantalum
  • Keyword: Relaxation
  • Keyword: Scattering

Source

  • Journal Name: Physical Review B; Journal Volume: 72; Journal Issue: 14

Collection

  • Name: Office of Scientific & Technical Information Technical Reports
    Code: OSTI

Institution

  • Name: UNT Libraries Government Documents Department
    Code: UNTGD

Resource Type

  • Article

Format

  • Text

Identifier

  • Report No.: UCRL-JRNL-212644
  • Grant Number: W-7405-ENG-48
  • Office of Scientific & Technical Information Report Number: 877928
  • Archival Resource Key: ark:/67531/metadc877423