The atomic oxygen density has been measured in the afterglow of a capillary nanosecond discharge in 24-30 mbar synthetic air (N 2 : O 2 = 4 : 1) by the two-photon absorption laser-induced fluorescence (TALIF) technique, combined with absolute calibration by comparison with xenon TALIF. The discharge was initiated by a train of 30 ns FWHM pulses of alternating positive-negative-positive polarity, separated by 250 ns, with a train repetition frequency of 10 Hz. The amplitude of the first pulse was 10 kV in the cable. A flow of synthetic air through the tube provided complete gas renewal between pulse trains. The O-atom density measurements were made over the time interval 200 ns-2 µs after the initial pulse. The gas temperature was determined by analysis of the molecular nitrogen second positive system optical emission spectrum. The influence of the gas temperature on the atom density measurements, and the reactions producing O atoms, are discussed.

This work aims to develop a controlled strategy for the growth of multifunctional core@shell nanoparticles based on Prussian blue analogues. We mainly focussed our attention on Rb 0.45 Co[Fe(CN) 6 ] 0.8 Á3H 2 O@Rb 0.2 Ni[Cr(CN) 6 ] 0.7 ÁzH 2 O particles, which combine a photoswitchable (photo-magnetic/-chromic) core with a ferromagnetic shell. The control of the chemical composition in the heterostructure is a key point to obtain the expected magnetic, optical and structural properties. We found that the removal of the unreacted species by washing after the growth of the primary particles led to an irreversible aggregation attributed to the desorption of stabilizing [Fe(CN) 6 ] surface units. We showed that this difficulty could be overcome by washing the particles in a solution containing chromicyanide ions, which are precursors of the Rb 0.2 Ni[Cr(CN) 6 ] 0.7 ÁzH 2 O shell phase, thus avoiding a contamination of the shell. Both X-ray diffraction and magnetic measurements confirmed that a controlled shell of the desired composition could be obtained this way.