Molecular dynamics simulation of Li surface erosion and bubble formation

Structure and dynamical properties of liquid Li containing He atoms were studied by the Molecular Dynamics method at various temperatures and densities and the diffusion coefficients were calculated. A new model of liquid Li surface is developed that shows the stratification of surface layers. The liquid Li sputtering yield, due to bombardment by slow He ions, was calculated for the new model and the result is compared with conventional models. Bubble formation in liquid Li is studied by simulation of cavity growth mechanisms in bulk liquid Li system wit 3-D periodic-boundary conditions. Our results show that small cavities are easily dissolved at certain temperatures. A cavity with a diameter of 50 A grows by consuming neighboring small cavities in accordance with the classical nucleation theory. The mechanism of bubble growth and explosion could significantly contribute to the surface erosion at high ion fluxes and explain some controversial experimental results.