  Line-by-line calculations are becoming the standard procedure for carrying
spectral simulations. However, it is important to insure the accuracy of such
spectral simulations through the choice of adapted models for the simulation of
key parameters such as line position, intensity, and shape. Moreover, it is
necessary to rely on accurate spectral data to guaranty the accuracy of the
simulated spectra. A discussion on the most accurate models available for such
calculations is presented for diatomic and linear polyatomic discrete
radiation, and possible reductions on the number of calculated lines are
discussed in order to reduce memory and computational overheads. Examples of
different approaches for the simulation of experimentally determined
low-pressure molecular spectra are presented. The accuracy of different
simulation approaches is discussed and it is verified that a careful choice of
applied computational models and spectroscopic datasets yields precise
approximations of the measured spectra.
