The quantum mechanical analysis for a non-resonant case of a single
radiation mode interacting with a two-level atom in a cavity is studied.
Expressions for the mean value of photon number and the time evolution of the
atomic motion are given. The
frequency of exchange energy between the atomic
levels and the radiation field systems for non- resonant and resonant
interactions is obtained. Results for all initial states of the atom-radiation field
are presented. Results for resonant and non-resonant interactions are
compared.