scholarly journals The Ratio DL/ for Electrons in Helium at 293 K

1974 ◽  
Vol 27 (2) ◽  
pp. 235 ◽  
Author(s):  
MT Elford
Keyword(s):  
Diffusion Coefficient ◽  
Momentum Transfer ◽  
Cross Section ◽  
Electron Mobility ◽  
Absolute Error ◽  
Longitudinal Diffusion ◽  
Experimental Errors ◽  
The Common ◽  
The Absolute ◽  
Momentum Transfer Cross Section

The Bradbury–Nielsen method has been used to measure the ratio of the longitudinal diffusion coefficient DL to the electron mobility μ in helium at 293 K over the E/N range 0024–0.607 Td. The absolute error is estimated to be less than � 3 %. The present results agree with those of Wagner et al. (1967), to within the combined experimental errors over the common range of E/N values, and are also compatible with the values predicted by Lowke and Parker (1969) from calculations based on the momentum transfer cross section of Crompton et al. (1967).

scholarly journals Drift Velocity and Longitudinal Diffusion Coefficient of Electrons in CO2?Ar Mixtures and Electron Collision Cross Sections for CO2 Molecules

1995 ◽  
Vol 48 (3) ◽  
pp. 357 ◽  
Author(s):  
Y Nakamura
Keyword(s):  
Diffusion Coefficient ◽  
Momentum Transfer ◽  
Cross Section ◽  
Drift Velocity ◽  
Cross Sections ◽  
Vibrational Excitation ◽  
Electron Collision ◽  
Longitudinal Diffusion ◽  
Excitation Cross Sections ◽  
Momentum Transfer Cross Section

The drift velocity and longitudinal diffusion coefficient of electrons in 0�2503% and 1� 97% C02-Ar mixtures were measured for 0�03 ~ E/N ~ 20 Td. The measured electron swarm parameters in the mixtures were used to derive a set of consistent vibrational excitation cross sections for the C02 molecule. Analysis of electron swarms in pure C02 using the present vibrational excitation cross sections was also carried out in order to determine a new momentum transfer cross section for the C02 molecule.

scholarly journals Computer Simulation of an Electron Swarm at low E/p in Helium

1974 ◽  
Vol 27 (1) ◽  
pp. 59 ◽  
Author(s):  
AI McIntosh
Keyword(s):  
Computer Simulation ◽  
Diffusion Coefficient ◽  
Cross Section ◽  
Electron Energy Distribution Function ◽  
Recent Theory ◽  
Electron Drift ◽  
Longitudinal Diffusion ◽  
Transverse Diffusion ◽  
And Diffusion ◽  
Momentum Transfer Cross Section

A computer simulated electron swarm at E/P293 = 1�0 V cm -1 tore 1 in a model gas has been used to examine the validity of a recent theory of electron drift and diffusion. The computed results are in agreement with well-established theories for the electron energy distribution function, drift velocity and transverse diffusion coefficient, and confirm that, for a constant momentum transfer cross section, the longitudinal diffusion coefficient is approximately half the transverse coefficient. However, significant differences have been found between the computed swarm and the predictions of the theory of Huxley (1972). In particular, over the time scale considered, the electron swarm is not symmetric about its centroid but is spatially anisotropic in such a way that it could appropriately be described as 'pear shaped'.

scholarly journals A Note on the Longitudinal Diffusion of Electrons in Argon

1972 ◽  
Vol 25 (5) ◽  
pp. 637 ◽  
Author(s):  
AG Robertson ◽  
JA Rees
Keyword(s):  
Electric Field ◽  
Momentum Transfer ◽  
Cross Section ◽  
Diffusion Coefficients ◽  
Applied Electric Field ◽  
Longitudinal Diffusion ◽  
Marked Influence ◽  
Momentum Transfer Cross Section

It has been shown both experimentally and theoretically that the diffusion of electrons subject to the influence of an applied electric field is often significantly different in directions parallel and normal to the electric field (Wagner, Davis, and Hurst 1967; Parker and Lowke 1969; Lowke and Parker 1969; Skullerud 1969). Lowke and Parker (1969) showed that the ratio of the diffusion coefficients (DL parallel to the electric field and DT normal to the field) is particularly sensitive to rapid variations with energy of the momentum transfer cross section of the electrons. It is to be expected therefore that for electrons in argon the Ramsauer?Townsend minimum in the momentum transfer cross section at energies of ~ 0�3 eV will have a marked influence on the value of DL.

scholarly journals Momentum Transfer Cross Section for e??Kr Scattering

1993 ◽  
Vol 46 (2) ◽  
pp. 249 ◽  
Author(s):  
MJ Brennan ◽  
KF Ness
Keyword(s):  
Energy Range ◽  
Momentum Transfer ◽  
Cross Section ◽  
Drift Velocity ◽  
Cross Sections ◽  
Theoretical Calculations ◽  
Transport Coefficients ◽  
Velocity Data ◽  
Experimental Errors ◽  
Momentum Transfer Cross Section

The momentum transfer cross section for electrons in krypton has been derived over the energy range Q-4 eV from an analysis of drift velocity and DT/I-' data for hydrogen-krypton mixtures. At energies in the vicinity of the Ramsauer-Townsend minimum, the present work differs significantly from derivations based on analyses of drift velocity data alone. The overall uncertainty in the derived cross section reflects the experimental errors in the transport coefficients, the uncertainty in the cross sections used to represent the hydrogen component in the mixtures, and the uncertainty associated with the X2 minimisation. The present cross section is compared with recent theoretical calculations and other experimental derivations.

scholarly journals The Diffusion Coefficient for Thermal Electrons in Mercury Vapour at 470 K

1980 ◽  
Vol 33 (6) ◽  
pp. 989 ◽  
Author(s):  
R Hegerberg ◽  
RW Crompton
Keyword(s):  
Diffusion Coefficient ◽  
Momentum Transfer ◽  
Cross Section ◽  
Cross Sections ◽  
Theoretical Calculations ◽  
Sampling Technique ◽  
Mercury Vapour ◽  
Velocity Data ◽  
Average Momentum ◽  
Momentum Transfer Cross Section

The diffusion coefficient for thermal electrons in mercury vapour has been measured using the CavaIIeri electron density sampling technique. The result indicates that the average momentum transfer cross section for electrons is ~27 x 10−16 cm2, a result which favours previously derived cross sections from drift velocity data over recent theoretical calculations.

scholarly journals The Cross Section for the J = 0 → 2 Rotational Excitation of Hydrogen by Slow Electrons

1969 ◽  
Vol 22 (6) ◽  
pp. 715 ◽  
Author(s):  
RW Crompton ◽  
DK Gibson ◽  
AI McIntosh
Keyword(s):  
Momentum Transfer ◽  
Cross Section ◽  
Cross Sections ◽  
Vibrational Excitation ◽  
The Cross ◽  
Excitation Processes ◽  
Slow Electrons ◽  
And Diffusion ◽  
Momentum Transfer Cross Section ◽  
Section Analysis

The results of electron drift and diffusion measurements in parahydrogen have been analysed to determine the cross sections for momentum transfer and for rotational and vibrational excitation. The limited number of possible excitation processes in parahydrogen and the wide separation of the thresholds for these processes make it possible to determine uniquely the J = 0 → 2 rotational cross section from threshold to 0.3 eV. In addition, the momentum transfer cross section has been determined for energies less than 2 eV and it is shown that, near threshold, a vibrational cross section compatible with the data must lie within relatively narrow limits. The problems of uniqueness and accuracy inherent in the swarm method of cross section analysis are discussed. The present results are compared with other recent theoretical and experimental determinations; the agreement with the most recent calculations of Henry and Lane is excellent.

Measurements of electron mobility and longitudinal diffusion coefficient in high pressure xenon doped with hydrogen

2019 ◽  
Vol 58 (3) ◽  
pp. 038001
Author(s):  
Hiroki Kusano ◽  
Mitsuhiro Miyajima ◽  
Nobuyuki Hasebe ◽  
Valery V. Dmitrenko
Keyword(s):  
High Pressure ◽  
Diffusion Coefficient ◽  
Electron Mobility ◽  
Longitudinal Diffusion
Sign in / Sign up

Export Citation Format

Share Document