Elastic He+ on He collision cross-sections and Monte Carlo calculation of the transport coefficients of He+ ions in gaseous helium
✍ Scribed by J.A.S. Barata; C.A.N. Conde
- Publisher
- Elsevier Science
- Year
- 2010
- Tongue
- English
- Weight
- 187 KB
- Volume
- 619
- Category
- Article
- ISSN
- 0168-9002
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✦ Synopsis
Integral and differential cross-sections for elastic collisions of He + ions in the ground state ( 2 S) with neutral He atoms are calculated, for centre-of-mass energies between 0.001 and 10 eV, using the partial waves method. The scattering phase shifts are calculated using the JWKB semi-classical approximation, with modified Tang-Toennies ion-atom (TTIA) potential energy curves, that describe spectroscopic data, dissociation energies and equilibrium internuclear distances, and the long-range interaction potentials. These cross-sections are used in a detailed three-dimensional Monte Carlo simulation model to calculate the main transport coefficients describing the ion drift through the neutral gas, as a function of the gas temperature and the reduced uniform electric field. Calculated drift velocities, ion mobilities, as well as longitudinal and transverse diffusion coefficients for He + atomic ions in gaseous He, at temperature T=293 K and reduced electric fields, E/N, in the 1 to 300 Td (1 Td = 10 À17 V cm 2 ) range, are reported and compared with the limited experimental data available in the scientific literature. The calculated drift velocities range from 28.31 m s À 1 at 1 Td to 3685.0 m s À 1 at 300 Td.