A Comparison of the Predictive Capabilities of the Embedded-Atom Method and Modified Embedded-Atom Method Potentials for Lithium

We compare six lithium potentials by examining their ability to predict coexistence properties and liquid structure using molecular dynamics. All potentials are of the embedded-atom method type. The coexistence properties we focus on are the melting curve, vapor pressure, saturated liquid density, and vapor-liquid surface tension. For each property studied, the simulation results are compared to available experimental data in order to properly assess the accuracy of each potential. We find that the Cui second nearest-neighbor modified embedded-atom method potential is overall the most reliable potential, giving adequate agreement for most of the properties examined. For example, the zero-pressure melting point of this potential is shown to be around 443 K, while it is it known from experiments to be about 454 K. This potential also gives excellent agreement for the saturated liquid densities, even though no liquid properties were used in the fitting procedure. We conclude that even though this potential is the most reliable overall, there is still room for improvement in terms of obtaining more accurate agreement for some of the properties studied, specifically the slope of the melting pressure versus temperature.