Molecular-dynamics simulation of molten alkali carbonates

Abstract

Molecular-dynamics simulations are performed on molten Li₂CO₃, Na₂CO₃, and K₂CO₃ in the N, V, T ensemble at 1200 K. The pair potentials contain only Coulomb interaction and Born-type repulsion, with a parametrization based upon ab initio interaction energies, from which electronic polarization effects have been subtracted. It is shown that, even at this level, a significant change in structure of the melt is observed on going from Li₂CO₃ to K₂CO₃. The self-diffusion constants of the ions are reproduced fairly well by the calculations. It is found that rotation of the CO^2- ₃ ions is substantially easier in K₂CO₃ than in Li₂CO₃.