Precision calculation of low-energy electron-impact excitation cross sections of helium among the ground and excited states

Zeng, De-Ling; Gao, Xiang; Han, Xuefeng; Li, Jiaming

doi:10.1103/physreva.91.022707

Cited by 4 publications

(10 citation statements)

References 42 publications

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“…In this work, we adopt the set 2 orbital basis of Ref. [20] to calculate the e-He collision excitation cross sections by the partial wave method using the FARM code. [35] More specifically, the adopted orbital basis includes the spec-troscopy orbitals nl (n = 1-3, l = 0-2) and the pseudo orbitals nl ( n = 4-6, l = 0-4), and 11 physical states are used to expand the (N + 1)-electron system.…”

Section: Scattering Amplitudementioning

confidence: 99%

“…The detailed description of the procedure to prepare the orbital basis and the convergence of the calculated total cross sections based on the basis can be found in Ref. [20]. In this work we only extend the calculations to a higher incident energy range.…”

Section: Scattering Amplitudementioning

confidence: 99%

“…Many calculations of electron-helium scattering have been performed experimentally (see review articles [11][12][13][14] and the references therein) and theoretically. [15][16][17][18][19][20][21][22] However, most of those studies mainly focused on the cross sections near the excitation threshold. Reference [21] (Fursa and Bray 1995) applied the convergent close-coupling (CCC) method to calculate e-He scattering cross section excited from the ground state in the incident energy range from 1.5 eV to 500 eV, where the overall agreement with the experimental data [23] is good, but without a detailed resonance structure.…”

Section: Introductionmentioning

confidence: 99%

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Electron impact excitation of helium atom

et al. 2015

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A method to deal with the electron impact excitation cross sections of an atom from low to high incident energies are presented. This method combines the partial wave method and the first Born approximation (FBA), i.e., replacing the several lowest partial wave cross sections of the total cross sections within FBA by the corresponding exact partial wave cross sections. A new set of codes are developed to calculate the FBA partial wave cross sections. Using this method, the convergent e–He collision cross sections of optical-forbidden and optical-allowed transitions at low to high incident energies are obtained. The calculation results demonstrate the validity and efficiency of the method.

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Section: Scattering Amplitudementioning

confidence: 99%

Section: Scattering Amplitudementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Electron impact excitation of helium atom

et al. 2015

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“…[4,5] Clegg showed for a sample of planetary nebulae (PNs) that the collision-to-recombination (C/R) correction (strongly dependent on the EIE cross sections) lowered the calculated He abundances by an average value of 10%. [4] Many experimental studies [6][7][8] and theoretical calculations [9][10][11][12][13][14] have been carried out to investigate the EIE cross sections of He in the last decades. However, most of the calculations focus on a specific energy region (either on low or high energy region).…”

Section: Introductionmentioning

confidence: 99%

An effective method to calculate the electron impact excitation cross sections of helium from ground state to a final channel in the whole energy region

Sun 孙,

Zeng 曾,

Jin 金

et al. 2023

Chinese Phys. B

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The electron impact excitation (EIE) cross sections of an atom/ion in the whole energy region are needed in many research fields, such as astrophysics studies, inertial confinement fusion researches and so on. In the present work, an effective method to calculate the EIE cross sections of an atom/ion in the whole energy region is presented. We use the EIE cross sections of Helium as an illustration example. The optical forbidden 11 S -n1 S (n = 2 - 4) and optical allowed 11 S -n1 P (n = 2 - 4) excitation cross sections are calculated in the whole energy region using a scheme that combines the partial wave R-matrix method and the first Born approximation. The calculated cross sections are in good agreement with the available experimental measurements. Based on these accurate cross sections of our calculation, we find that the ratios between the accurate cross sections and Born cross sections are nearly the same for different excitation final states in the same channel. According to this interesting property, a universal correction function is proposed and given to calculate the accurate EIE cross sections with the same computational efforts of the widely used Born cross sections, which should be very useful in the related application fields.

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“…It is generally accepted that the R-matrix type methods are good candidates to obtain the required atomic data 9 – 15 . But for the conventional R-matrix method: 1) it’s hard to assure the accuracies for each level/resonance 16 , 17 ; 2) a very fine energy grid is needed to guarantee all the levels/resonances without missing any lines; 3) it’s not trivial to determine and assign all the levels and resonances precisely.…”

Section: Introductionmentioning

confidence: 99%

Analytical Property of Scattering Matrix:Spectroscopy Phenomena and Sharp Overlapping Autoionization Resonances

Jin

Han

Gao

et al. 2017

Sci Rep

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An extended atomic data base with sufficiently high precision is required in astrophysics studies and the energy researches. For example, there are “infinite” energy levels in discrete energy region as well as overlapping resonances in autoionization region. We show in this paper the merits of our relativistic eigenchannel R-matrix method R-R-Eigen based on the analytical continuation properties of scattering matrices for the calculations of the energy levels, overlapping resonances and the related transitions. Using Ne+ as an illustration example, the scattering matrices of Ne+ in both discrete and continuum energy regions are calculated by our R-R-Eigen method directly. Based on our proposed projected high dimensional quantum-defect graph (symmetrized), one can readily determine the accuracies of the calculated scattering matrices using the experimental energy levels in a systematical way. The calculated resonant photoionization cross sections in the autoionization region are in excellent agreement with the benchmark high resolution experiments. With the scattering matrices checked/calibrated against spectroscopy data in both discrete and continuum energy regions, the relevant dynamical processes should be calculated with adequate accuracies. It should then satisfy the needs of the astrophysical and energy researches.

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Precision calculation of low-energy electron-impact excitation cross sections of helium among the ground and excited states

Cited by 4 publications

References 42 publications

Electron impact excitation of helium atom

Electron impact excitation of helium atom

An effective method to calculate the electron impact excitation cross sections of helium from ground state to a final channel in the whole energy region

Analytical Property of Scattering Matrix:Spectroscopy Phenomena and Sharp Overlapping Autoionization Resonances

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