Monte Carlo simulation of ion-ion recombination in methane and sulphur hexafluoride

Abstract

Recombination of ions in mixtures of methane and sulphur hexafluoride has been simulated in Monte Carlo technique. The results of the simulation can be directly compared with experimental measurements. As a function of gas pressure, the recombination rate has a maximum of approximately 10-6 cm3 s-1 at a pressure of 1 atm, in good agreement with experimental results.

A mass spectrometric study of positive and negative ion formation in an SF6corona. I. Sources of sulphur-fluoride ions

“…having a rate constant -lo-' cm3 SK' (Littlewood and Pyle 1990), to account for any significant loss of SF:.…”

Synergistic effect in the rate of three-body ion - ion recombination in gas mixtures

“…in the CH 4 :SF 6 :He = (1 − δ)/2:(1 − δ)/2:δ mixtures at 300 K. To obtain the recombination rate in one-component gases at low pressures we used the method of Flannery (1980) for charge transfer scattering between CH + 4 and CH 4 and that of Bates and Mendas (1982) for elastic polarization scattering between SF − 6 (SF 6 ) and SF 6 . For the ion mobilities we took the data by Littlewood and Pyle (1990a) who have performed Monte Carlo simulation to calculate the recombination coefficient under the considered conditions and obtained the result which is in a good agreement with data measured by Littlewood (1990) at moderate pressures (200-600 Torr). Figure 3 shows our results in comparison with the Monte Carlo results by Littlewood and Pyle (1990a).…”

“…For the ion mobilities we took the data by Littlewood and Pyle (1990a) who have performed Monte Carlo simulation to calculate the recombination coefficient under the considered conditions and obtained the result which is in a good agreement with data measured by Littlewood (1990) at moderate pressures (200-600 Torr). Figure 3 shows our results in comparison with the Monte Carlo results by Littlewood and Pyle (1990a). Our calculation agrees rather well with the Monte Carlo simulation and shows the pronounced synergism in the pressure range of 550 < p < 920 Torr which is explained in the same terms as that for process (21) in the He:Ar mixture.…”

“…First, a field hinders recombination by raising the kinetic energy of the ions; this is governed by reduced electric field E/N. Second, in the presence of a field the Littlewood and Pyle (1990a).…”

“…The pressure and temperature dependencies of the recombination rate in a pure gas are well understood. Although there are some investigations of the ion-ion recombination in gas mixtures (Cornell and Littlewood 1987, Littlewood and Pyle 1990a, Littlewood 1990), relatively little is known about the dependence of the rate of process (1) on the gas composition.…”