Electron-impact excitation of the<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msup><mml:mrow><mml:mi mathvariant="italic">n</mml:mi></mml:mrow><mml:mrow><mml:mn>1</mml:mn></mml:mrow></mml:msup></mml:mrow></mml:math><i>P</i>levels of helium: Theory and experiment

Cartwright, D. C.; Csanak, G.; Trajmar, S.; Register, D. F.

doi:10.1103/physreva.45.1602

Cited by 80 publications

(57 citation statements)

References 56 publications

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“…2 1 P transition. Our FBA results are compared with those of Cartwright et al 25 We find agreement between the two calculations in the scattering angle intervals [0,20] and [60,100]. A small disagreement is seen in the interval ]20, 60[.…”

Section: Resultssupporting

confidence: 75%

Electron impact excitation of helium in Debye plasma

et al. 2015

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The probability, differential, and integral scattering cross sections of the 11S→21S and 11S→21P transitions of helium have been calculated in the first Born approximation. The projectile-target interactions depending on the temperature and the density of plasma are described by the Debye-Hückel model. Wave functions of the target before and after collision were modeled by non orthogonal Hartree-Fock orbitals. The wave functions parameters are calculated with the Ritz variational method. We improve our unscreened first Born approximation integral cross sections by using the BE-scaled (B stands for binding energy and E excitation energy) method. The second Born approximation has also been used to calculate the excitation cross sections in Debye plasma. Our calculations are compared to other theoretical and experimental results where applicable.

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Section: Resultssupporting

confidence: 75%

Electron impact excitation of helium in Debye plasma

et al. 2015

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“…This can be attributed to the fact that the angular resolution error of the apparatus is possibly larger for He atoms than for other targets. The evaluation of the correction to be applied to the data of [16,17] due to forward elastic scattering in He is difficult to perform on the basis of existing experimental [55] and theoretical data [7,27,56]. In particular, existing measurements of differential cross sections for elastic scattering [57], electronic excitation [58] and ionization [59] do not extend to very low scattering angles.…”

Section: Heliummentioning

confidence: 98%

“…The Ar data are within 4.4% from the [21]; full triangles, Dalba [16,17]; the open diamond at 3 KeV is from de Heer and Jansen [14]; continuous line, fit with (1). Ionization cross sections: open squares, de Heer and Jansen [14]; full inverted open triangles, Krishnakumar and Srivastava [36]; full squares Nagy et al [37]; continuous line, fit with (4) Excitation cross sections: open circles, FOMBT calculation from Cartwright [27]; continuous line, fit with (3); Elastic cross sections: full circles, de Heer et Jansen [14]; diamonds, de Heer and Jansen [53]; dot-dashed line, elastic cross section obtained as difference by (9) (i.e. fitted total less fitted excitation and ionization cross sections); dashed line, elastic cross section obtained as difference by (9) but fitting the total cross section data of [16,17] corrected for an error increasing from 0% at 200 eV up to 30% at 3000 eV [21]; full triangles, Zecca et al [18]; continuous line, fit with (1).…”

Section: Gasmentioning

confidence: 99%

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Analytical partitioning of total cross sections for electron scattering on noble gases

Brusa

Karwasz

Zecca

1996

Z Phys D - Atoms, Molecules and Clusters

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Empirical analytical formulae are proposed, aiming at the description of partial cross sections for electron scattering on noble gases. Selected measurements of total, excitation and ionization cross sections for these gases have been fitted by these analytical formulae in the 20-5000 eV energy range. The elastic cross sections, obtained as the difference, compare quite well with the elastic experimental data for all gases but for helium. The difference elastic cross sections were fitted by a cross section formula derived from electron scattering on a single or double Yukawa potential in the first Born approximation. Our analysis shows a good consistency between partial and total cross sections for the four heavier gases. For helium, we suggest the possibility of large errors in the high energy part of total, elastic and excitation cross sections. The analytical expressions given in this paper allow to reproduce the total and partial cross sections within the measurement errors in a large energy range from a few tens of eV, up to several keV. PACS: 34.80.Bm; 34.80.Dp I IntroductionElectron-atom and electron-molecule cross section data are important in a large variety of applications and fields (see for instance [1]). In these applications, cross section values as a function of the energy are needed as input data in calculations, modelling and Monte Carlo simulations. Some examples can be found in [2] for plasma chemistry, in [3] for fusion plasma research, and in [4] for electron and positron slowing down and diffusion in solids. Many applications of electron impact ionization cross sections (from gas discharges to astrophysics and atmospheric physics) presented by different authors, are reported in [5].An obvious help to these computational works can be provided by analytical or empirical expressions describing the cross sections data [6][7][8][9]. Where these formulae are not available, tables of data and interpolations or extrapolations must be used. Analytical representation are also interesting by themselves giving direct information on the consistency of different data sets, and allowing extrapolation of cross section data at energies where experimental measurements do not exist. Moreover, some insight and information on the type of interaction can be gained. In our recent studies [10-13] we have measured the electron scattering total cross sections on three families of molecules in the 70-4000 eV energy range and described these cross sections from a few tens of eV to 4000 eV by a simple analytical formula using two or four adjustable parameters. In this paper we present a partitioning scheme for electron scattering on noble gases, where the total and the partial cross sections are approximated by analytical formulae.To date, a relatively large number of good quality electron scattering measurements on noble gases cover an energy range from less than 1 eV to 3000 eV. The works of de Heer and Jansen [14] on He, de Heer et al. [15] on Ne, Ar, Kr, Xe, present a comprehensive evaluation of semiempirical values...

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“…The processes of electron interactions with noble gas atoms are well studied. The cross sections for elastic and inelastic electron collisions with helium atoms are presented in (Rejoub et al, 2002;Saha, 1989;Cartwright & et al, 1992) and those with xenon atoms can be found in (Rejoub et al, 2002;NIFS;Hyman, 1979). Knowing the electron energy distribution function, it is possible to analyze the distribution of the power introduced into the discharge among the most important electron processes.…”

Section: Electron Energy Distribution Functionmentioning

confidence: 99%