QUANTUM MOLECULAR-DYNAMICS SIMULATIONS OF LIQUID ALKALIS

We employ a unified molecular dynamics (MD), quantum mechanical approa ch to simulate the behavior of large collections of atoms at finite te mperature. The nuclei are moved according to classical mechanics while the forces are computed via quantum mechanical models. Two approaches have been used: (1) the extended Huckel method, which is an approxima te molecular orbital approach and (2) density functional theory based on the local density approximation and plane wave pseudopotential form ulation. We compute properties from the MD trajectories of up to 4 ps duration for samples containing up to 250 atoms of lithium, sodium, an d potassium. These results are compared to both previous calculations and experimental results.