Electron excitation from the 1<sup>1</sup>S, 2<sup>3</sup>S and 2<sup>1</sup>S states of helium. An eleven-state R-matrix calculation
K A Berrington; P G Burke; L C G Freitas; A E Kingston; K A Berrington; Dept. of Appl. Math. & Theor. Phys., Queen's Univ. of Belfast, UK; P G Burke; Dept. of Appl. Math. & Theor. Phys., Queen's Univ. of Belfast, UK; L C G Freitas; Dept. of Appl. Math. & Theor. Phys., Queen's Univ. of Belfast, UK; A E Kingston; Dept. of Appl. Math. & Theor. Phys., Queen's Univ. of Belfast, UK
Журнал:
Journal of Physics B: Atomic and Molecular Physics
Дата:
1985-10-28
Аннотация:
An R-matrix calculation for electron-helium scattering is described in which the eleven lowest target states of helium are included, using configuration interaction wavefunctions. Excitation cross sections are calculated up to 30 eV from the 1<sup>1</sup>S ground state and the metastable 2<sup>3</sup>S and 2<sup>1</sup>S states of helium to the higher n=2 states, and, for the first time in an ab initio calculation, to the n=3 states. The authors confirm their preliminary finding that the explicit coupling of the n=3 channels significantly reduces the cross sections calculated in an earlier five-state approximation, by up to 50% for n=1 to n=2 transitions at energies above the n=3 thresholds. Using the new cross section data, rate coefficients are calculated for temperatures up to 50000K for the transitions considered.
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