We present a detailed analysis of the dynamical behavior of an optically pumped molecular laser. This study combines bifurcation and power spectral analysis with numerical investigation of the global features of attractor topology under control parameter variation. The special role of the pump laser in generating physically distinct periodic and chaotic dynamics is emphasized through the complementary use of laser gain and dispersion characteristics. Our main results are the following: (i) instabilities associated with the physically distinct mechanisms of relaxation and pump-induced Rabi sideband oscillations are readily generated; (ii) the topological characteristics of both periodic and chaotic attractors reflect these physically distinct mechanisms, making it possible to discriminate between both types of behavior in heterodyne power spectra; and (iii) the ratio of deenergization to dipole-dephasing rates is central to determining the operating characteristics of the laser. © 1989 The American Physical Society.