Electron thermalization in gases. II. Neon, argon, krypton, and xenon

Journal Article · Sun Jun 01 04:00:00 EDT 1980 · J. Chem. Phys.; (United States)

DOI:https://doi.org/10.1063/1.439043· OSTI ID:5428626

Mozumder, A

Following the theoretical procedure outlined in an earlier paper (J. Chem. Phys. 72, 1657 (1980)), hereinafter referred as I, the present work in an extension to the other rare gases. The following quantities are computed and evaluated: thermalization time and the position distribution at thermalization, time-dependent relaxation rates and evolutions of the directed velocity, width of the positional distribution, and the diffusion coefficient. A Newtonian cooling law has been demonstrated when the effective electron temperature is close to the gas temperature with an equation for the relaxation time of the excess electron temperature. Weighted moments of the form M/sub n/=/sub T/ have been calculated for n=1 to 10, where sigma/sub m/ is the momentum transfer cross section and the symbol <--->/sub T/ denotes averaging with respect to the equilibrium electron velocity distribution at T. The fifth and the seventh moments are related, respectively, to the energy loss rate when is >>T and to the Newtonian cooling rate then approx. =T. As in I the thermalization parameters are largely independent of initial velocity if the initial electron kinetic energy is much greater than that for the Ramsauer minimum (Ar, Kr, and Xe). Otherwise the thermalization time is considerably reduced. A somewhat analogous situation in neon is attributed to the ''incipient'' Ramsauer effect. Thermalization time at gas temperature approx.300 K increases, according to the present work, in the sequence He, Xe, Kr, Ne, Ar which is contributed jointly by the mass ratio and the behavior of momentum transfer cross section at low energies including the presence or absence of the Ramsauer effect. Comparison with experiments have been made where possible.

• Research Organization: Radiation Laboratory and the Department of Chemistry, University of Notre Dame, Notre Dame, Indiana 46556
• OSTI ID: 5428626
• Journal Information: J. Chem. Phys.; (United States), Journal Name: J. Chem. Phys.; (United States) Vol. 72:11; ISSN JCPSA
• Country of Publication: United States
• Language: English

Related Subjects

640304* -- Atomic
Molecular &amp; Chemical Physics-- Collision Phenomena
74 ATOMIC AND MOLECULAR PHYSICS
ARGON
ATOM COLLISIONS
COLLISIONS
CROSS SECTIONS
DISTRIBUTION FUNCTIONS
ELECTRON COLLISIONS
ELECTRON-ATOM COLLISIONS
ELEMENTS
ENERGY LOSSES
KRYPTON
LOSSES
MOMENTUM TRANSFER
NEON
NONMETALS
RARE GASES
RELAXATION
SLOWING-DOWN
THERMALIZATION
TRANSPORT THEORY
XENON