On the convergence of close-coupling results for low-energy electron scattering from magnesium
Bartschat, K., Zatsarinny, O., Bray, I., Fursa, D.V. and Stelbovics, A.T. (2004) On the convergence of close-coupling results for low-energy electron scattering from magnesium. Journal of Physics B: Atomic, Molecular and Optical Physics, 37 (13).
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We use three different implementations of the non-relativistic close-coupling method to investigate the convergence of theoretical predictions for electron scattering from magnesium at impact energies below 1 eV. It is found that the convergence of the close-coupling expansion is extremely slow, particularly for the L = 1 partial wave that is dominated by a shape-resonance common to many similar quasi-two-electron systems. An accurate prediction of the scattering length (we obtain −2.4 ± 0.1 a0) is also a nontrivial problem. Although the shape resonance in the L = 1 channel can be predicted in agreement with experiment already in small close-coupling expansions with three or nine coupled states (see Bartschat and Sadeghpour 2003 J. Phys. B: At. Mol. Opt. Phys. 36 L9 for details), this fortuitous agreement is due to simultaneously inaccurate descriptions of both the N-electron target and the (N + 1)-electron collision problems. We demonstrate how a more systematic though slow convergence pattern of the close-coupling expansion can be achieved by concentrating on a highly accurate target description before attempting to solve the collision problem.
|Publication Type:||Journal Article|
|Murdoch Affiliation:||Centre for Atomic, Molecular and Surface Physics|
|Publisher:||Institute of Physics|
|Copyright:||2004 IOP Publishing Ltd|
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