Figure 9: Radiative lifetimes of various Ps states as a function of the principal quantum number . The lifetimes were calculated by summing the Einstein coefficients of all electric-dipole-allowed decay channels from each Rydberg state. For each coefficient the appropriate radial integrals were determined using analytic expressions for the radial wave functions in a pure Coulomb potential [53]. The dashed line is the annihilation lifetime of s states. After [5].