Centrifugal barrier effects in metallic clusters

We report calculations of Rydberg states for spherical metallic clusters. These calculations demonstrate that centrifugal barrier effects operate, but that they act differently from the situation in atoms. Instead of orbital collapse, one sees a characteristic flattening of the effective potential: for Na-9 and K-9 it occurs for the l = 2 Rydberg electron, and for Na-21 and K-21, the l = 3 Rydberg electron, which become very sensitive to core polarization effects. The effect of the centrifugal barrier on the quantum defects has been explored for various values of angular momentum.