New technique for molecular-dynamics computer simulations: Hellmann-Feynman theorem and subspace Hamiltonian approach.

In the past, molecular-dynamics computer simulations have employed model potentials of the interaction between atoms. Here we introduce a new molecular-dynamics technique in which atomic forces are computed from the total electronic energy of the system of interacting atoms. The method is illustrated by trajectories for Al and As atoms scattering off the relaxed (110) surface of GaAs.