The calculation of electron energy distributions and attachment coefficient for electron swarms in oxygen

Abstract

Electron energy distributions have been calculated for electron swarms in oxygen for 15 less-than-or-eq, slant E/N less-than-or-eq, slant 152 Td. These distributions satisfy the experimentally measured values of both drift velocity and the diffusion coefficient, and allowed the theoretical value of the rate of attachment (ηv) to be calculated to an accuracy of ±3%.The calculated values of η/N are dependent upon the measured values of the drift velocity, but since the latter show a large variation, the η/N values have been represented by two limiting curves. The important feature of these curves is that η/N quickly rises to its maximum value at about E/N=30 Td, from which it only gradually reduces as E/N increases. It has also been possible to obtain values of the momentum transfer cross section in oxygen for electron energies up to 10 eV. This cross section was found to have a simple form and to be very close in value to the total cross section.