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Phys 498CQM Lecture Notes 17
Car-Parrinello simulations

Monday, March 26, 2001
Lecturer: Richard Martin

Reading:
Thijssen, 9.1-9.3

  1. Brief outline of classical molecular dynamics
    • Verlet algorithm for numerical integration of coupled F=ma equations
    • Simulated annealing to lowest energy state
  2. Forces on atoms from the electrons - the Hellmann-Feynman theorem
    • The electron density alone is sufficient to determine forces
  3. The Car-Parrinello Methods
    • References
      R. Car and M. Parrinello, Phys. Rev. Lett. 55, 2471 (1985)
      (the original - very readable)
      J. Garner, Computers in Physics 4, 395 (1990). Nice discussion; simple exampl es.
      M. Payne, et. al., Rev Mod. Phys. 64, 1045, (1992). Most complete recent large review
    • Solution of quantum equations by classical molecular dynamics
      • Solving quantum equations by using a "fictitious mass" and a fictitious set of Newtonian equations
      • Annealing by reducing the temperature leads system to ground state - the same solution as found by matrix diagonalization
      • Examples of simple quantum systems
        • A simple 2 x 2 Hamiltonian - solution by Car-Parrinello molecular dynamics and "simulated annealing"
        • Particle in a box
    • FFT's instead of dense matrix multiplication
    • Examples of use in large scale calculations
      • "Ab Initio" Molecular dynamics of solids and liquids
      • The real Newtonian equations for atoms with forces from electrons from the Helmann-Feynman theorem
      • Example: melting of Carbon

Next time: Continue Car-Parrinello discussion as needed
Conclusion of first part of course on independent particle problem


Last Modified March 28
Email question/comments/corrections to rmartin@uiuc.edu .