Structure and dynamics of bulk liquid Ga and the liquid-vapor interface:: An ab initio study

The static and dynamic structure of bulk liquid gallium is studied by using the orbital-free ab initio molecular dynamics method. Three thermodynamic states along the coexistence line are considered, namely, T=373, 523, and 959 K for which x-ray and/or neutron scattering data are available. The calculated static structure shows good agreement with the available experimental data. The dynamical structure reveals collective density excitations with an associated dispersion relation, which closely follows recent experimental data. Results have also been obtained for several transport coefficients. The overall picture is that the dynamic properties have many characteristics of the simple liquid metals. Additional simulations have also been performed on the structure of the free liquid surface associated with those thermodynamic states. We analyze its oscillatory ionic and valence electronic longitudinal density profiles, and comparison is made with the corresponding experimental data.