Dissociative Recombination of Acetone Fragments, Adducts, and Dimer Ions.

The room temperature dissociative recombination of ions formed in an acetone/argon plasma has been studied using the flowing afterglow Langmuir probe-mass spectrometer method. By changing the concentration of acetone density, it is possible to have a plasma dominated by different types of ions (fragments, adducts, and dimer ions). The application of these measurements to astrophysical plasmas is discussed.

Oxidation-Induced Surface Roughening of Aluminum Nanoparticles Formed in an Ablation Plume.

Nanoparticles formed within an ablation plume produced by the impact of a nanosecond laser pulse on the surface of an aluminum target have been directly measured using small-angle x-ray scattering. The target was immersed in an oxygen-nitrogen gas mixture at atmospheric pressure with the O_{2}/N_{2} ratio being precisely controlled. The results for an increasing oxygen content reveal remarkable effects on the morphology of the generated particles, which include a decrease in the particle volume but a marked increase in its surface ruggedness.

X-ray Photoelectron Spectroscopy of Isolated Nanoparticles.

X-ray photoelectron spectroscopy (XPS) is a very efficient and still progressing surface analysis technique. However, when applied to nano-objects, this technique faces drawbacks due to interactions with the substrate and sample charging effects. We present a new experimental approach to XPS based on coupling soft X-ray synchrotron radiation with an in-vacuum beam of free nanoparticles, focused by an aerodynamic lens system.

Observations of Ball-Lightning-Like Plasmoids Ejected from Silicon by Localized Microwaves.

This paper presents experimental characterization of plasmoids (fireballs) obtained by directing localized microwave power (<1 kW at 2.45 GHz) onto a silicon-based substrate in a microwave cavity. The plasmoid emerges up from the hotspot created in the solid substrate into the air within the microwave cavity.