  Synthetic stellar spectra are extensively used for many different
applications in astronomy, from stellar studies (such as in the determination
of atmospheric parameters of observed stellar spectra), to extragalactic
studies (e.g. as one of the main ingredients of stellar population models). One
of the main ingredients of synthetic spectral libraries are the atomic and
molecular line lists, which contain the data required to model all the
absorption lines that should appear in these spectra. Although currently
available line lists contain millions of lines, a relatively small fraction of
these lines have accurate derived or measured transition parameters. As a
consequence, many of these lines contain errors in the electronic transition
parameters that can reach up to 200%. Furthermore, even for the Sun, our
closest and most studied star, state-of-the-art synthetic spectra does not
reproduce all the observed lines, indicating transitions that are missing in
the line lists of the computed synthetic spectra. Given the importance and wide
range of applications of these models, improvement of their quality is urgently
necessary. In this work we catalogued missing lines in the atomic and molecular
line lists used for the calculation of the synthetic spectra in the region of
GAIA, comparing a solar model computed via a recent line list with a high
quality solar atlas available in the literature. After that, we attempted the
calibration of their atomic parameters with the code ALLiCE; the calibrated
line parameters are publicly available for use.
