Near-threshold vibrational excitation and elastic electron scattering from N<sub>2</sub>

Sohn, Woon Yong; Kochem, K H; Scheuerlein, K M; Jung, K.; Ehrhardt, H.

doi:10.1088/0022-3700/19/23/019

Cited by 40 publications

(23 citation statements)

References 19 publications

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“…We begin with three energies below the resonance (0.55, 1.0, and 1.5 eV), then turn to six above it (4.0, 5.0, 6.0, 7.0, 8.0, and 10.0 eV)energies chosen in part to facilitate comparison to the several other measured and' calculated elastic e-N2 DCSs in the literature. Our results at below-resonance energies appear in Tables IV and V. Figure 7(a) compares the present elastic DCSs at our lowest energy, 0.55 eV, with those from previous measurements by Sohn et al [54] and by Shi, Stephen, and Burrow [58]. Agreement between the present experimental and theoretical results is generally good.…”

Section: Nonresonant Elastic Scatteringsupporting

confidence: 85%

“….2~I i I I i~I i I In addition to the present experimental (solid circles) and theoretical (solid lines) results, we show the data of Sohn et al. [54] (open triangles) and in (a) and (c) of Shi, Stephen, and Burrow [58] (open squares). Also shown in (c) are measured DCSs of Shyn and Carignan [45] (open circles) and the hybrid-theory results of Chandra and Temkin [34] (long-dashed line) and Schwinger multichannel DCSs of Huo et al.…”

Section: Nonresonant Elastic Scatteringsupporting

confidence: 53%

“…More interesting difFerences appear in The most extensively studied energy for elastic e-N2 scattering is 1.5 eV. Previous measurements include those by Shyn and Carignan [45], Sohn et al [54], Brennan et al [57], and Shi, Stephen, and Burrow [58]; previous calculations include hybrid-theory calculations by Chandra and Temkin [34], Schwinger multichannel cal-culations by Huo et al [30], and rigid-rotor calculations by Morrison, Saha, and Gibson [61]. Indeed, the lack of agreement at this energy between previous experimental and theoretical DCSs motivated (in part) the recent experimental investigations of Brennan et al , Shi, Stephen, and Burrow, and the present work.…”

Section: Nonresonant Elastic Scatteringmentioning

confidence: 98%

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Detailed theoretical and experimental analysis of low-energy electron-N2scattering

et al. 1995

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We have carried out a comprehensive theoretical and experimental study of electron scattering from molecular nitrogen at energies below 10.0 eV. In the theoretical component of this project we have generated differential and integral cross sections for elastic scattering and vibrational excitation in converged vibrational close-coupling calculations. In the experiments, we have measured dift'erential cross sections for these processes at scattering angles from 20' to 130 in a crossed-beam experiment at a large number of energies between 0.55 and 10 eV and, in a complementary time-of-Right experiment, total cross sections at energies between 0.08 and 10.0 eV. The measured angular distributions have been extrapolated to 0 and 180 using a procedure based on a nonlinear least-squares fit constrained by known physical properties of the e-Nz scattering matrix; numerical integration of the resulting extrapolated distributions yields integrated cross sections with almost no error beyond that inherent in the measured angular data. We find generally good agreement between the present experimental and theoretical cross section, particularly at energies near the H~r esonance near 2.39 eV. In previous studies of scattering in this region, such comparisons have been made problematical by the difhculty of ascertaining the appropriate theoretical scattering energy. We recommend here a protocol for resolving this problem for both elastic scattering and vibrational excitation.PACS number(s): 34.80.6s

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Section: Nonresonant Elastic Scatteringsupporting

confidence: 85%

Section: Nonresonant Elastic Scatteringsupporting

confidence: 53%

Section: Nonresonant Elastic Scatteringmentioning

confidence: 98%

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Detailed theoretical and experimental analysis of low-energy electron-N2scattering

et al. 1995

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“…[42] The elastic scattering cross sections are based on the work by LaBahn and Callaway [1970], Williams [1975], Blaha and Davis [1975], Williams and Allen [1989], Bray et al [1991] and Mayol and Salvat [1997] for atomic species (H, He, N and O), Sohn et al [1986], García and Blanco [2001] and Itikawa [2006] for N 2 , Itikawa [2002] and Morrison et al [1977] for CO 2 , Kanik et al [1992] for CO, as well as Jain and Baluja [1992] and Brunger et al [1991] for H 2 . For the electronic excitation of atomic species, we adopt the cross sections of Stone et al [2002] for H and He, Laher and Gilmore [1990] for O, Goembel [1991, 1992] and Yang and Doering [1996] for N. For electron impact ionization, the cross sections of Bartlett and Stelbovics [2004] are used for H, He and N, and those of Laher and Gilmore [1990] are used for O.…”

Section: Discussionmentioning

confidence: 99%

Suprathermal electron spectra in the Venus ionosphere

et al. 2011

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[1] In this study, a multistream kinetic model is used to derive the suprathermal electron intensity in the Venus ionosphere, to be compared with the observations made by the Analyzer of Space Plasmas and Energetic Atoms (ASPERA-4) Electron Spectrometer (ELS) instrument onboard Venus Express (VEx) on 18 May 2006. Input parameters of the model are chosen to be consistent with the detailed ephemeris information. We consider two cases for the magnetic field line configuration. The first assumes vertical magnetic field lines, while in the second the configuration is consistent with the VEx Magnetometer (MAG) measurements for that particular orbit. The model calculations suggest that the energy spectrum of suprathermal electrons not only depends on the local photoelectron production but is also strongly influenced by transport as well as energy degradation. We confirm the postulation of Coates et al. (2008) (2008). The model results indicate that the condition of local equilibrium is satisfied for suprathermal electrons below ∼155 km on Venus. However, transport becomes effective at higher altitudes, significantly altering the secondary electron production rate and leading to strongly anisotropic suprathermal electron flow. For the case with the MAG-derived, slanted magnetic field configuration, we make a data-model comparison in terms of both the absolute magnitude of the suprathermal electron intensity and the appearance of spectral peaks. The comparison suggests that the actual magnetic field lines are probably inclined more vertically than a simple extrapolation from the MAG measurements.

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“…The cross section is dominated by the well-known 2 Π g resonance centered around 2.3 eV. [14], and the theoretical results of Feng et al [15,16] (DSG model) are shown for comparison. three incident energies marked by bars in figure 2.…”

Section: Nitrogenmentioning

confidence: 95%

Improved techniques of measuring accurate electron - molecule cross sections near threshold and over a large angular range

Allan

2007

AIP Conference Proceedings

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Abstract. Methods to measure absolute differential elastic and vibrational excitation cross sections using an electron spectrometer with a magnetic angle changer are discussed. Emphasized are the need to by-pass drifts and to properly correct for the instrumental response function when angle of detection or electron energy are varied. The results are illustrated with cross sections in nitrogen, methane and neopentane. The good agreement of the results with the experimental data from other leading groups (taken mostly without the angle changer) and with some theories indicate that the measurements are reliable. The angle-integrated data agrees well with the results of electrontransport experiments. Good agreement with theory is obtained for nitrogen, even in the difficult low-energy region. Electronic excitation in rare gases is also briefly mentioned.

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Near-threshold vibrational excitation and elastic electron scattering from N₂

Cited by 40 publications

References 19 publications

Detailed theoretical and experimental analysis of low-energy electron-N2scattering

Detailed theoretical and experimental analysis of low-energy electron-N2scattering

Suprathermal electron spectra in the Venus ionosphere

Improved techniques of measuring accurate electron - molecule cross sections near threshold and over a large angular range

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Near-threshold vibrational excitation and elastic electron scattering from N2

Cited by 40 publications

References 19 publications

Detailed theoretical and experimental analysis of low-energy electron-N2scattering

Detailed theoretical and experimental analysis of low-energy electron-N2scattering

Suprathermal electron spectra in the Venus ionosphere

Improved techniques of measuring accurate electron - molecule cross sections near threshold and over a large angular range

Contact Info

Product

Resources

About

Near-threshold vibrational excitation and elastic electron scattering from N₂