How strongly correlated is MnSi?
  We present an experimental study of the electronic structure of MnSi. Using X-ray Absorption Spectroscopy, X-ray photoemission and X-ray fluorescence we provide experimental evidence that MnSi has a mixed valence ground state. We show that self consistent LDA supercell calculations cannot replicate the XAS spectra of MnSi, while a good match is achieved within the atomic multiplet theory assuming a mixed valence ground state. We discuss the role of the electron-electron interactions in this compound and estimate that the valence fluctuations are suppressed by a factor of 2.5, which means that the Coulomb repulsion is not negligible. 
F. Carbone, M. Zangrando, A. Brinkman, A. Nicolaou, F. Bondino, E.   Magnano, A.A. Nugroho, Th. Jarlborg, F. Parmigiani and ...