Electronic structure of magnetic molecules V15: LDA+U calculations, X-ray emission and photoelectron spectra

Electronic structure of V$_{15}$ magnetic molecules (K$_6$ [V$_{15}$ As$_6$ O$_{42}$ (H$_2$O)] cdot 8H$_2$O)$ has been studied using LSDA+U band structure calculations, and measurements of X-ray photoelectron (valence band, core levels) and X-ray fluorescence spectra (vanadium K$beta_5$ and L$_{2,3}$, and oxygen K$alpha$). Experiments confirm that vanadium ions are tetravalent in V$_{15}$, and their local atomic structure is close to that of CaV$_3$O$_7$. Comparison of experimental data with the results of electronic structure calculations show that the LSDA+U method provides a description of the electronic structure of V$_{15}$ which agrees well with experiments.