Phenomenological model for the statistical study of charged metal clusters

We develop a phenomenological model to represent surface charge in microscopic treatments of finite metal systems. This model is simple enough to allow for extensive simulations and global optimization for systems having as much as several hundred atoms. Applications to the Coulombic and thermal stabilities of multiply charged sodium clusters show a good agreement of the appearance sizes with experimental data at high temperatures, as well as systematic deviations to the Rayleigh limit at zero temperature. Statistical investigations also give evidence for a significant charge dependence of both the fragmentation patterns and the solid-liquid phase transition. [S0163-1829(99)13447-7].