  The revival structure and evolution of Rydberg wave packets are studied on a
time scale much greater than the revival time $t_{\rm rev}$. We find a new
level of revival structure and periodic motion different from that of the known
fractional revivals. The new sequence of revivals culminates with the formation
of a wave packet that more closely resembles the initial packet than does the
full revival at time $t_{\rm rev}$. We refer to such a revival as a
superrevival. We also show that an initial radial wave packet may be described
as a type of squeezed state known as a radial squeezed state. Our results apply
not only for hydrogenic wave packets, but for wave packets in alkali-metal
atoms as well in the context of quantum defect theory.
