I participate to the research group GDR REST (REncontres de Spectroscopie Theorique). Our project aims to bring together different communities of theoretical spectroscopy in order to establish the state-of-the-art approaches on the market, share knowledge, identify important issues and unresolved problems, and indicate future directions.There are several approaches to the study of elementary excitations, the choicebeing based on the kind of elementary excitations as well as systems one is interested in. In particular: Theoretical developments for the description of excited states; Density-based approaches for the theoretical spectroscopy; Many-body approaches for theoretical spectroscopy. The GDR REST aims at achieving several objectives, both scientific and general federating objectives: Excitations of Valence electrons and Core electrons; From Weak correlation to strong correlation; Linear and non-linear optics.
For more information go to our website:  http://gdr-rest.polytechnique.fr