NEW TECHNIQUE FOR MOLECULAR DYNAMICS COMPUTER SIMULATIONS: HELLMANN-FEYNMAN THEOREM AND SUBSPACE HAMILTONIAN (GREEN'S FUNCTION) APPROACH.

In the past, molecular dynamics computer simulations have employed model potentials of interaction between atoms - usually two-body potentials such as the Lennard-Jones potential. These model potentials are valuable for obtaining a qualitative understanding of many phenomena, but do not permit quantitative calculations for covalently-bonded materials. We introduce a new molecular dynamics technique in which atomic forces are computed from the total electronic energy of the system of interacting atoms, i. e. , the motion of the nuclei is treated classically, but the electrons are treated quantum-mechanically. The technique employs the Hellmann-Feynman theorem and the subspace Hamiltonian approach. We represent the electronic structure by a semiempirical tight-binding Hamiltonian. The method is illustrated by trajectories for Al and As atoms scattering off the relaxed (110) surface of GaAs.

NEW TECHNIQUE FOR MOLECULAR DYNAMICS COMPUTER SIMULATIONS: HELLMANN-FEYNMAN THEOREM AND SUBSPACE HAMILTONIAN (GREEN'S FUNCTION) APPROACH. Conference Paper