  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.
