SEMICLASSICAL MECHANICS OF PERIODIC MOTION - I - GENERAL SCHEME

A unified treatment of quantum mechanical oscillatory motion in one di mension is presented in a phase space formalism which is especially ad apted to the semiclassical energy domain and closely related to a 'nai ve' quantization of action and angle variables. Characteristics of thi s scheme are non-classical symmetry properties of the phase space func tions representing density operators and observables and the inclusion of half-Bohr orbits besides the familiar Bohr orbits. Over long time intervals the quantum evolution can be well approximated by a Hamilton ian flow along these distinguished classical orbits. The interplay of this reduced classical evolution and the symmetry properties of the ph ase space functions results in a consistent quantitative description o f quantum interference effects which are most clearly seen in the revi vals of wavepackets.