Contribution of electron-atom collisions to the plasma conductivity of noble gases

Abstract

We present an approach which allows the consistent treatment of bound states in the context of the dc conductivity in dense partially ionized noble gas plasmas. Besides electron-ion and electronelectron collisions, further collision mechanisms owing to neutral constituents are taken into account. Especially at low temperatures T ≈ 1eV, electron-atom collisions give a substantial contribution to the relevant correlation functions. We suggest an optical potential for the description of the electronatom scattering which is applicable for all noble gases. The electron-atom momentum-transfer cross section is in agreement with experimental scattering data. In addition the influence of the medium is analysed, the optical potential is advanced including screening effects. The position of the Ramsauer minimum is influenced by the plasma. Alternative approaches for the electron-atom potential are discussed. Calculations of the electrical conductivity are compared with experimental data.

Optical reflectivity based on the effective interaction potentials of xenon plasma

“…This indicates that, in contrast to the former calculations, a systematic treatment of electron–atom collisions is essential. For a detailed treatment of electron–atom collisions, see also Rosmej et al and Adams et al We conclude that the use of the dynamic potential leads to a good agreement with results obtained from the simulations performed in Norman and Saitov …”

“…A more general form for the collision frequency is given by ν ( ω ) = r ( n , T , ω ) ν ( ω ) (1) , where the expression for r ( n , T , ω ) is given in terms of equilibrium correlation functions. For fully ionized plasmas in the static limit, ω → 0, the renormalization function interpolates between the low‐density Spitzer limit and the high‐degeneracy Ziman limit , . The renormalization function depends on the frequency ω and approaches the high‐frequency limit 1, .…”

Impact of quantum non‐locality and electronic non‐ideality on e–He scattering in a dense plasma

“…The screened HF interaction potential is repulsive at large distances. This repulsion is a result of the plasma polarization around the atom , . Considering the screened HF interaction potential, from Figure a we see that, in comparison with the case of λ = 0, the quantum non‐locality ( λ ≠ 0) leads to a stronger repulsion at large distances and to the stronger attraction at close inter‐particle distances.…”

“…In Figure a, the transport cross‐sections calculated using the screened optical potential (sum of potentials and ) and the optical potential for the isolated atom–electron interaction are compared with the experimental data by Crompton et al and Register et al Additionally, in Figure the results of Rosmej et al and Adibzadeh and Theodosiou are shown. The calculations of Adibzadeh and Theodosiou are for the isolated atom–electron scattering, and the result of Rosmej et al was obtained on the basis of the optical potential taking into account the exchange potential and screening by a classical plasma.…”

“…Study of the electron–helium scattering allows to calculate transport properties of plasmas . An accurate calculation of the scattering cross‐sections (e.g., elastic, transport) requires the construction of the pair interaction potential taking into account screening by free electrons, partial screening by bound electrons, and exchange effects in the interaction of the scattering electron with the shell electrons , . Approximating the Slater sum as a product of pair contributions, Nagel et al showed that an electron–atom interaction potential can be presented as a sum of the direct term screened by bound electrons without any exchange contributions and the exchange term.…”