Coupled-channels optical calculation of electron-hydrogen resonances

McCarthy, Ian E.; Shang, Bo

doi:10.1103/physreva.46.3959

Cited by 25 publications

(14 citation statements)

References 12 publications

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“…2] and that the 15-state results on integral cross sections differ from the experiments by around 10% leads us to the measure of importance of the continuum effects. This is confirmed by the most recent coupled-channels-optical (6CCO) calculation of McCarthy and Shang[25].Figures 1 and 2 alsoshow that the matching between the qualitative shape of the 15-state results arid the experiments is most impressive.…”

supporting

confidence: 75%

“…For visual clarity, the 6CCO calculations [25] are presented as vertical offsets and the vertical increments are given in the brackets. Two important observations are noted: (i) The impressive agreement in details between the shape of the 15- [25]. One reason for this could be the fact that the density distribution of energy points used in the calculation is not high enough to portray the complicated structure of.…”

Section: A the 1s~2s And 1s -+2s+2p Integral Cross Sectionsmentioning

confidence: 99%

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15-stateR-matrix investigation of resonances in the inelastic scattering of electrons from atomic hydrogen at energies up to 13.06 eV

Ratnavelu

1994

Phys. Rev. A

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A 15-state R-matrix calculation has been carried out at 530 energies ranging from the n =2 threshold up to n =5 threshold at 13. 06 eV to map out the resonant profiles for the n =2 inelastic integral and differential cross sections, and the angular distribution of the spin asymmetry in the inelastic scattering of spin-polarized electrons by the spin-polarized hydrogen atoms at angles 0', 30', 55', 70', 90', 125', and 180' for the 1s~2s transition. The calculations are compared with the experiments and the feasibility studies of using the electron-energy-loss experiments in the investigation of resonances with positions higher than the n =2 threshold have been carried out.

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supporting

confidence: 75%

Section: A the 1s~2s And 1s -+2s+2p Integral Cross Sectionsmentioning

confidence: 99%

15-stateR-matrix investigation of resonances in the inelastic scattering of electrons from atomic hydrogen at energies up to 13.06 eV

Ratnavelu

1994

Phys. Rev. A

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“…The CCO method for electron-atom scattering given by McCarthy and Stelbovics [7] has been applied to study the energy-dependent phenomena in electron-hydrogen scattering [8], negative-ion resonances in an electron-sodium system [9], and in an electron-oxygen system [10]. Good agreements were achieved with results of experimental measurements and other theoretical calculations.…”

Section: Introductionmentioning

confidence: 82%

Resonance phenomena ine+-Li collisions

Liu¹,

Cheng²,

Zhou³

et al. 2011

Phys. Rev. A

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“…Another use for a convergent calculation is to test methods that may be simpler, or more widely applicable, but still take into account all channels ab initio. Such a method is the coupled-channels-optical method, whose equivalent local implementation (Lower et al 1987) has been applied to the present problem by McCarthy and Shang (1992). For this method the n = 2 integrated cross sections differ only in minor detail from the CCC results.…”

Section: L246mentioning

confidence: 99%

Comparison of convergent electron - hydrogen calculations

Bray

McCarthy

Stelbovics

1996

J. Phys. B: At. Mol. Opt. Phys.

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Abstract. Integrated cross sections for the n = 1 and 2 states of atomic hydrogen are calculated by the convergent-close-coupling method for a range of closely spaced energies just above the n = 2 threshold. The cross sections are compared with those calculated by a pseudo-state calculation, and two other methods that also converge, in principle, to the exact result. These are the intermediate-energy R-matrix method and the convergent J -matrix method. Experimental data are described very well by all of these theories.Three types of calculation that converge, in principle, to the exact solution of the electronatom scattering problem are applied to the electron-hydrogen problem at energies just above the n = 2 excitation threshold.The intermediate-energy R-matrix (IERM) method (Burke et al 1987) has recently been applied to this problem by Odgers et al (1995). In this method the Schrödinger equation for the interaction of two electrons and a proton is solved inside a spherical box, chosen so that exchange can be neglected in the external region. The solution is matched to external solutions with appropriate boundary conditions. Loss of flux into the continuum is accounted for by describing the motion of the atomic electron in terms of the same one-electron bound and continuum basis as is used to describe the motion of the scattering electron. R-matrix methods are convenient for calculating a range of closely spaced energies, once the internal solution has been computed.Odgers et al display the effect of the target continuum in their calculation by comparing it with a 15-state R-matrix calculation by Fon et al (1995), which has essentially converged to the limit of a close-coupling calculation that couples only discrete channels. Just above the n = 2 threshold the effect of the continuum is a substantial reduction in the integrated cross sections for n = 2 excitations.The J -matrix (JM) method (Broad and Reinhardt 1976) has been applied to hydrogen in a similar energy region by Konovalov and McCarthy (1994). In this method the Schrödinger equation for the scattering problem is solved in a square-integrable basis, for which both the atomic and scattering electron are represented by finite sets of Laguerre functions. Cross sections converge as the basis size is increased. Calculation of cross sections for a range of closely spaced energies involves little more computational labour than for a single energy.The IERM results presented by Odgers et al (1995) and JM cross sections for n = 2 excitations differ, usually by up to 20% (Odgers et al 1995) in the energy range below §

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Coupled-channels optical calculation of electron-hydrogen resonances

Cited by 25 publications

References 12 publications

15-stateR-matrix investigation of resonances in the inelastic scattering of electrons from atomic hydrogen at energies up to 13.06 eV

15-stateR-matrix investigation of resonances in the inelastic scattering of electrons from atomic hydrogen at energies up to 13.06 eV

Resonance phenomena ine+-Li collisions

Comparison of convergent electron - hydrogen calculations

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