The University of Milan (UMIL) gathers researchers from the Theoretical Spectroscopy research group of the Physics Department. The UMIL unit has long-time experience in the first-principle investigation of the properties of real materials at the atomic/molecular length-scale, especially concerning surfaces, molecules, interfaces, as well as nanostructures and 2D materials. The investigation of valence/core-level and optical excitations is deeply rooted in the unit research interests.