Table 2: The -dependence of several properties of Rydberg atoms, with examples shown for the 30 d state of Ps, H, and He. The state separation is calculated for 30 d31 d. The orbital radius is defined here as the expectation value , where includes the relevant quantum defect. The electric dipole moment-to-mass ratios are calculated for the outermost state of the = 30, = 2 Stark manifold. The radiative lifetime -dependence applies only to low states: for circular states, the scaling is closer to (see Figure 9).