First Principles Molecular Dynamics for Extended Length and Time Scales

Anders Niklasson
Theoretical Division
Los Alamos National Laboratory
Los Alamos, NM 87544, USA


As the available computational capacity for scientific computing is growing, first principles Born-Oppenheimer molecular dynamics (BOMD) is becoming an increasingly important tool for studying a wide range of material problems. BOMD offers a very accurate quantum based approach to atomistic simulations that is more reliable and general compared to classical molecular dynamics. Unfortunatley, BOMD simulations based on, for example, density functional theory, are often limited by a very high computational cost or by fundamental shortcomings such as unbalanced phase space trajectories, numerical instabilities and a systematic long-term energy drift. I will present some of our recent attempts to avoid these limitations, which include reduced complexity solvers (that are ideal for GPU implementations) and an extended Lagrangian formulation of BOMD that enables an efficient and energy conserving geometric integration of the equations of motion even under incomplete and approximate numerical convergence of the electronic ground state optimization.

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