Monte Carlo simulation of the reaction and transport of negative ions O- and O2- in oxygen

Abstract

Properties of the O- and O2- ion swarm in oxygen are studied by a Monte Carlo simulation technique for E/N values from 5 to 200 Td (1 Td=0.354 V cm-1 Torr-1 at 0 degrees C). The generation and loss reactions of the ions, such as dissociative attachment, electron detachment and charge transfer, as encountered in electron avalanches in oxygen, are taken into account. The results show that the values of the ion mobility, diffusion coefficients and detachment and charge transfer coefficients are in reasonable agreement with experiments. With O- ions the drift velocity, defined as the centre-of-mass velocity of an ion swarm, is found to be smaller than that defined as the velocity averaged in the velocity space, as E/N>or approximately=80 Td.