Theoretical spectroscopy

This issue is dedicated to \textquotedblleftTheoretical Spectroscopy\textquotedblright. It is meant to give an overview of what this branch of physics is able to contribute today to the progress of science, combining theory developments, the building of complex computer codes, and large scale numerical calculations. Complementary to experiment and to modeling considerations, theoretical spectroscopy yields new understanding and predictions concerning novel materials. The questions that are treated range from abstract theory to problems of technological interest. Theoretical Spectroscopy is a field that undergoes rapid development; here we give a snapshot of its capabilities today. To cite this article: L. Reining, C. R. Physique 10 (2009). \textcopyright 2009 Published by Elsevier Masson SAS on behalf of Académie des sciences.