The distribution of arrival time spectra (ATS) of electrons in nitrogen and carbon dioxide has been measured over the range of E/N from 20 to 1000 Td (1 ) at room temperature by a double-shutter drift tube. The drift velocity of electrons in and was evaluated from these distributions by the ATS method. Moreover, the ratio of the longitudinal diffusion coefficient to the electron mobility was measured. The values of and in and were in good agreement with experimental and theoretical values obtained by previous investigators except for a few of the earlier studies.

The electron swarm behaviour in nitrogen is studied for E/ rho 0 from 20 to 200 V cm-1 Torr-1 by a Boltzmann equation method. A set of electron collision cross sections is determined using newly published data. The modification of these cross sections when necessary is kept to within experimental error. Moreover, the validity of the vibrational excitation cross sections obtained theoretically by Hazi and co-workers (1981) is examined. The results show that the calculated swarm parameters are in close agreement with those obtained by a photon flux experiment of Wedding and co-workers (1985). This suggests that the set of electron collision cross sections determined in the present work is an appropriate one as far as the swarm parameter analysis is concerned. The electron energy distribution and electronic excitation coefficients and frequencies to various excited states are also calculated and discussed.

Electron swarm parameters, such as the drift velocity and the ionization coefficient, in water vapor have been measured for relatively wide ranges in reduced electric fields (E/N) at room temperature. The drift velocity (W m ) was obtained based upon the arrival-time spectra of electrons by using a double-shutter drift tube for the E/N from 60 to 1000 Td, while the first and second ionization coefficients (α and γ) were determined by the steady-state Townsend (SST) method from 50 to 3000 Td. The comparison between the results and other data in the literature shows that our results for both the drift velocity and the effective ionization coefficient are lower than those of the other data in the above ranges.

This paper reports on Monte Carlo simulations of electrons in liquid water using a set of electron collision cross sections constructed with data published recently. The track history of electrons having initial energy ranged from 1keV to 10keV is investigated looking at the ionization and excitation processes. The results show that the ratio of the ionization and excitation events per track history is unique independent of the initial electron energy above a couple of hundred eV and these inelastic processes occur with low energy electrons frequently below 100eV. In particular, the excitation processes are dominated by the electrons below 50eV. Flight distance distributions between the inelastic collisions are also discussed.