Semiclassical Spectra from Periodic-Orbit Clusters in a Mixed Phase Space.

We calculate complete quasienergy spectra (rather than partial information thereon) from classical periodic orbits for the kicked top, throughout the transition from integrability to well-developed chaos. The standard error incurred for the quasienergies is a small percentage of their mean spacing, even though the effective Planck constant is not pushed to small values. The price paid is the inclusion of collective contributions of clusters of periodic orbits near bifurcations into Gutzwiller's trace formula