  Both unitary evolution and the effects of dissipation and decoherence for a
general three-level system are of widespread interest in quantum optics,
molecular physics, and elsewhere. A previous paper presented a technique for
solving the time-dependent operator equations involved but under certain
restrictive conditions. We now extend our results to a general three-level
system with arbitrary time-dependent Hamiltonians and Lindblad operators.
Analytical handling of the SU(3) algebra of the eight operators involved leaves
behind a set of coupled first-order differential equations for classical
functions. Solution of this set gives a complete solution of the quantum
problem, without having to invoke rotating-wave or other approximations.
Numerical illustrations are given.
