The Computation of Local Stress in ab initio Molecular Simulations
Provides a theoretical framework for local stress computation in quantum-mechanical molecular simulations, addressing a need in material science.
This work derives formulas for computing local stress in ab initio molecular dynamics simulations, covering Born-Oppenheimer and Ehrenfest dynamics with tight-binding and real-space methods. The formulas are validated against full ab initio simulations.
Motivated by the increasingly more important role of ab initio molecular dynamics models in material simulations, this work focuses on the definition of local stress, when the forces are determined from quantum-mechanical descriptions. Two types of ab initio models, including the Born-Oppenheimer and Ehrenfest dynamics, are considered. In addition, formulas are derived for both tight-binding and real-space methods for the approximations of the quantum-mechanical models. The formulas are examined via comparisons with full ab initio molecular simulations.