We measured the band spectra (first and second positive systems) of the nitrogen molecule to examine the vibrational and rotational temperatures of the CΠ3 and BΠ3 states by optical emission spectroscopy. We compared the experimentally measured and the calculated spectra to determine those temperatures of the generated plasma. We generated a microwave discharge nitrogen plasma in a cylindrical quartz tube (26mm inside diameter) with a discharge pressure of 0.5–1.0Torr. The microwave frequency was 2.45GHz and the output power was set at 600W. It was found that Tv≈0.5–0.7eV and Tr≈0.07–0.15eV at BΠ3 (v=7, 8, and 9), whereas Tv≈0.65–0.9eV and Tr≈0.06–0.16eV at CΠ3 (v=0 and 1). Both rotational temperatures obtained from first and second positive systems were in good agreement. We also compared the measured vibrational populations with theoretical calculations, in which vibrational distribution function at N2 X and electron energy distribution function are calculated self-consistently.

The dissociation degrees of N2 and O2 are examined in a nitrogen–oxygen mixed microwave discharge plasma in a cylindrical quartz tube of 26 mm inner diameter with a discharge pressure of 0.5–1.0 Torr and a microwave power of 600 W by the actinometry method. We measured the electron temperature and density with a Langmuir double probe, while the vibrational and rotational temperatures of the first and second positive bands of N2 were measured by optical emission spectroscopy. Even when the line intensity of atomic nitrogen was weak and partly coincided with the high-intensity band spectrum of the first positive system due to its small dissociation degree, the actinometry method was found to be feasible when the first positive band spectrum, calculated as a function of the rotational and vibrational temperatures, was subtracted from that observed experimentally. It was found that the dissociation degrees of both N2 and O2 increase with the molar ratio of nitrogen in the mixed N2–O2 discharge gas for the same total discharge pressure. The experimental results are discussed by comparison with a simple numerical model based on chemical kinetics in the plasma. It was found that the dissociation of oxygen molecules is enhanced by the collision with excited nitrogen molecules, particularly those with metastable states, whereas that of nitrogen is suppressed by an admixture of oxygen molecules due to the chemical quenching processes of nitrogen atoms.

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The structure of AF-ZrF(4) system (A(+) = Li(+), Na(+), K(+)) compounds in the liquid state is studied using an approach combining EXAFS spectroscopy with molecular dynamics simulations. A very good agreement is observed between the two techniques, which allows us to propose a quantitative description of the liquids. From the Zr(4+) 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(4). At that particular composition, the ZrF(6)(2-) 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(4). The most important differences are observed for the lifetime of these octahedral units, which increases importantly with the size of the monovalent cation. On a larger scale, an intense first sharp diffraction peak is observed for the Zr(4+)-Zr(4+) partial structure factor, which can be attributed to the correlations between the octahedral units formed.

Platinum (Pt) nanosheets were developed by exfoliating layered platinum oxide. Moreover, we succeeded in synthesizing monolayer Pt nanosheets for the first time by adjusting the conditions for reduction. Monolayer Pt nanosheets were highly active in oxygen reduction reaction.