Embedded-ion method: An analytical energy-conserving charge-transfer interatomic potential and its application to the La-Br system

作者：Zhou X W^*; Doty F P

来源：Physical Review B, 2008, 78(22): 224307.

DOI：10.1103/PhysRevB.78.224307

• charge transfer states
• crystal structure
• lanthanum compounds
• molecular dynamics method
• potential energy functions
• stoichiometry

Molecular-dynamics simulations of ionically bonded material systems with nonstoichiometric composition, interfaces or surfaces, defects, or other local environments that are substantially different from a stoichiometric bulk require the use of a variable charge interatomic potential. In conventional variable charge molecular-dynamics simulations, the charges on atoms are solved by minimizing the system potential energy with respect to charges. The reduced potential energy during this energy minimization process is not accounted for in the force calculation and therefore does not contribute to a corresponding increase in the kinetic energies of atoms. As a result, the total system energy decays over time. This energy nonconserving behavior precludes the method from being used to study problems such as thermal transport and thermal diffusion. It may also lead to inaccurate results for other types of simulations. Here we attempt to overcome this problem by analytically incorporating variable charge concepts into an embedded-ion method, which has mathematical format similar to the well-known embedded-atom method. We illustrate the approach using the La-Br system.

• 出版日期2008-12