%0 Journal Article %A Pedio, M. %A Wu, Z. Y. %A Benfatto, M. %A Mascaraque Susunaga, Arantzazu %A Michel, E. %A Ottaviani, C. %A Crotti, C. %A Peloi, M. %A Zacchigna, M. %A Comicioli, C. %T NEXAFS experiment and multiple scattering calculations on KO_2: effects on the π resonance in the solid phase %D 2002 %@ 0163-1829 %U https://hdl.handle.net/20.500.14352/59404 %X The high-energy resolution O K-edge absorption near-edge x-ray absorption fine structure spectrum has been measured for in situ prepared potassium superoxide. The experimental data have been analyzed in detail by multiple scattering calculations using self-consistent field potentials. In particular, the so-called π resonance at the rising edge, which presents a double-peak structure, has been totally resolved and reproduced by the calculations. This analysis indicates that the grown material is arranged in a KO_2 structure with an O-O distance between 1.31 and 1.34 Angstrom. Moreover, the calculation demonstrates both a complete ionic character of the bound between the Oˆ(2-) anion and K atoms and a strong interaction between the anion and solid-state matrices. %~