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Pauvert, O.*; Salanne, M.*; Zanghi, D.*; Simon, C.*; Reguer, S.*; Thiaudire, D.*; Okamoto, Yoshihiro; Matsuura, Haruaki*; Bessada, C.*
Journal of Physical Chemistry B, 115(29), p.9160 - 9167, 2011/07
Times Cited Count:62 Percentile:81.96(Chemistry, Physical)The structure of molten AF-ZrF system (A=Li, Na, K) is studied using EXAFS spectroscopy with molecular dynamics simulations. From the Zr solvation shell point of view, we observe a progressive stabilization of the 7-fold and then of the 6-fold coordinated complexes when passing from Li to Na and K as a "counterion". Particular attention is given to the systems consisting of 35 mol% of ZrF. At that particular composition, the ZrF complex predominates largely whatever the nature of the alkali. The calculated vibrational properties of this complex are in excellent agreement with a previous Raman spectroscopy experiment on molten KF-ZrF. The most important differences are observed for the lifetime of these octahedral units. On a larger scale, an intense first sharp diffraction peak is observed for the Zr-Zr partial structure factor, which can be attributed to the correlations between the octahedral units formed.
Pauvert, O.*; Zanghi, D.*; Salanne, M.*; Simon, C.*; Rakhamatullin, A.*; Matsuura, Haruaki*; Okamoto, Yoshihiro; Vivet, F.*; Bessada, C.*
Journal of Physical Chemistry B, 114(19), p.6472 - 6479, 2010/05
Times Cited Count:59 Percentile:79.5(Chemistry, Physical)The structure of the molten LiF-ZrF system up to 50 mol% ZrF was investigated by combining high-temperature nuclear magnetic resonance (NMR) and extended X-ray absorption fine structure (EXAFS) experiments with molecular dynamics (MD) calculations. Zr high-temperature NMR experiments give an average coordination of 7 for the zirconium ion on all domains of composition. MD simulations, in agreement with EXAFS experiments at the K-edge of Zr, provide evidence for the coexistence of three different Zr-based complexes, [ZrF], [ZrF], and [ZrF], in the melt.