Studies on the Transport of Ions in Gases: Theory, Experiments and Applications

Publications

Measuring the mobilities of the ions formed in P-10 mixtures

Publication . Neves, P. N. B.; Trindade, A. M. F.; Barata, J. A. S.; de Oliveira Pegado de Noronha E Távora, Luís Miguel; Conde, C. A. N.

We measured the reduced mobilities (k0 in cm2V -1s-1) of the ions that are formed in P-10 mixtures under different pressures and various reduced electric fields. Two types of ions were identified. We then used the extrapolated values of k0 when E/N→0 (2.41 and 2.76 cm2V-1s-1), the Langevin formula and the Blanc's law, to calculate the masses of these ions. Calculations indicate that the two ions have masses of 41 a.u. and 25 a.u., respectively. We propose hypothesis to explain the nature and origin of those ions.

2009-11Conference paper

Open access

Experimental measurement of the mobilities of atomic and dimer Ar, Kr, and Xe ions in their parent gases

Publication . Neves, P. N. B.; Conde, C. A. N.; Távora, L. M. N.

A new experimental technique for measuring the mobilities of positive ions in their parent gases is presented. The technique was applied to the rare gases, Ar, Kr, and Xe, and, for pressures typically below 10 Torr, two different types of positive ions were observed. The reduced mobilities of these ions in their parent gases were measured as a function of E/N, the ratio of the electric field strength to the gas number density, at a temperature of 300±1 K. The results were compared with others available in the literature and the two ions were identified as being the atomic and the dimer rare gas ions. The results are in good agreement with those from other authors. Space charge and impurities effects are discussed.

2010-09-29Journal article

Restricted access

The X++2X→X2++X reaction rate constant for Ar, Kr and Xe, at 300 K

Publication . Neves, P. N. B.; Conde, C. A. N.; Távora, L. M. N.

The X++2X → X+2X- reaction rate constants were measured for Ar, Kr and Xe, at 300 K, using a new experimental technique. The results for Ar, kAr=(1.2 ± 0.2) × 10 -31 cm6 Kr, kKr=(2.1 ± 0.9) × 10-31 cm and Xe, kxe=(1.48 ± 0.18) x 10 -31 cm6S-1 are discussed and compared with those of other authors using different techniques.

2010-07Journal article

Restricted access

Keywords

Ion-Atom Collision Cross-Sections,Ion Transport in Gases,Ion Mobility Spectrometry,Radiation Detector Physics, Engineering and technology ,Engineering and technology/Chemical engineering

Funding agency

Fundação para a Ciência e a Tecnologia, I.P.
Fundação para a Ciência e a Tecnologia, I.P.

Funding programme

5876-PPCDTI
Concurso para Projectos de I&D em todos os Domínios Científicos - 2006

Funding Award Number

PTDC/FIS/65569/2006