DYNAMIC PROPERTIES OF LIQUID-METALS

The static and dynamic properties of three liquid alkali metals were s tudied using molecular dynamics: lithium (at 470 K), rubidium (over a temperature range from 350 to 1873 K) and cesium (just above the melti ng point, at 308 K). The interatomic potential is based for Li on an O PW pseudopotential and for Rb and Cs on an empty-core pseudopotential. From the raw computer data, both single-particle and collective dynam ic correlation functions were extracted. Interpretation of these corre lation functions in terms of hydrodynamic, memory-function and (simple ) mode-coupling models allows one to derive both thermodynamic and ela stic properties. The dynamic structure factors have been compared for all three metals with recent neutron-scattering data. It is found that - except for the higher temperature states of Rb (i.e., at the onset of the metal-non-metal transition) - agreement between theory and expe riment is good. Concerning elastic and thermodynamic properties, diffe rences of 10 15% with respect to the experimental data are encountered .