  The highly convergent iterative methods developed by Trujillo Bueno and
Fabiani Bendicho (1995) for radiative transfer (RT) applications are
generalized to spherical symmetry with velocity fields. These RT methods are
based on Jacobi, Gauss-Seidel (GS), and SOR iteration and they form the basis
of a new NLTE multilevel transfer code for atomic and molecular lines. The
benchmark tests carried out so far are presented and discussed. The main aim is
to develop a number of powerful RT tools for the theoretical interpretation of
molecular spectra.
