Negative ion resonance measurements in the autoionizing region of helium measured across the complete angular scattering range (0°-180°)

Excitation function measurements for the decay of the 2s22p 2P and 2s2p2 2D triply excited negative ion resonances in helium to singly excited n = 2 states have been measured. These excitation functions have been determined across the complete angular range (0–180°) using a magnetic angle changer wi...

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Main Authors: Ward, R., Cubric, D., Bowring, N., King, G, Read, F., Fursa, Dmitry, Bray, Igor
Format: Journal Article
Published: IOP Publishing 2013
Subjects:
Online Access:http://hdl.handle.net/20.500.11937/5582
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author Ward, R.
Cubric, D.
Bowring, N.
King, G
Read, F.
Fursa, Dmitry
Bray, Igor
author_facet Ward, R.
Cubric, D.
Bowring, N.
King, G
Read, F.
Fursa, Dmitry
Bray, Igor
author_sort Ward, R.
building Curtin Institutional Repository
collection Online Access
description Excitation function measurements for the decay of the 2s22p 2P and 2s2p2 2D triply excited negative ion resonances in helium to singly excited n = 2 states have been measured. These excitation functions have been determined across the complete angular range (0–180°) using a magnetic angle changer with a soft-iron core. The convergent close-coupling method has been used to calculate the cross sections, with the underlying complexity of the problem not yet being able to be fully resolved. Agreement between the present experimental data and previous experimental data is good, with these excitation functions confirming the presence of an unusual (2s22p)2P resonance behaviour in the 21S channel at 90°, where this would not usually be expected. Resonance energy and width values have been obtained, with a mean energy for the (2s22p)2P resonance of 57.20 ± 0.08 eV and a mean width of 73 ± 20 meV, and a mean energy of the (2s2p2)2D resonance of 58.30 ± 0.08 eV and a mean width of 59 ± 27 meV. Resonant cross section and ρ2 values have been calculated across the angular range for the first time, providing angular distribution data on decay propensities for both resonances.
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publishDate 2013
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spelling curtin-20.500.11937-55822018-03-29T09:05:43Z Negative ion resonance measurements in the autoionizing region of helium measured across the complete angular scattering range (0°-180°) Ward, R. Cubric, D. Bowring, N. King, G Read, F. Fursa, Dmitry Bray, Igor atomic and molecular physics computational physics Excitation function measurements for the decay of the 2s22p 2P and 2s2p2 2D triply excited negative ion resonances in helium to singly excited n = 2 states have been measured. These excitation functions have been determined across the complete angular range (0–180°) using a magnetic angle changer with a soft-iron core. The convergent close-coupling method has been used to calculate the cross sections, with the underlying complexity of the problem not yet being able to be fully resolved. Agreement between the present experimental data and previous experimental data is good, with these excitation functions confirming the presence of an unusual (2s22p)2P resonance behaviour in the 21S channel at 90°, where this would not usually be expected. Resonance energy and width values have been obtained, with a mean energy for the (2s22p)2P resonance of 57.20 ± 0.08 eV and a mean width of 73 ± 20 meV, and a mean energy of the (2s2p2)2D resonance of 58.30 ± 0.08 eV and a mean width of 59 ± 27 meV. Resonant cross section and ρ2 values have been calculated across the angular range for the first time, providing angular distribution data on decay propensities for both resonances. 2013 Journal Article http://hdl.handle.net/20.500.11937/5582 10.1088/0953-4075/46/3/035001 IOP Publishing restricted
spellingShingle atomic and molecular physics
computational physics
Ward, R.
Cubric, D.
Bowring, N.
King, G
Read, F.
Fursa, Dmitry
Bray, Igor
Negative ion resonance measurements in the autoionizing region of helium measured across the complete angular scattering range (0°-180°)
title Negative ion resonance measurements in the autoionizing region of helium measured across the complete angular scattering range (0°-180°)
title_full Negative ion resonance measurements in the autoionizing region of helium measured across the complete angular scattering range (0°-180°)
title_fullStr Negative ion resonance measurements in the autoionizing region of helium measured across the complete angular scattering range (0°-180°)
title_full_unstemmed Negative ion resonance measurements in the autoionizing region of helium measured across the complete angular scattering range (0°-180°)
title_short Negative ion resonance measurements in the autoionizing region of helium measured across the complete angular scattering range (0°-180°)
title_sort negative ion resonance measurements in the autoionizing region of helium measured across the complete angular scattering range (0°-180°)
topic atomic and molecular physics
computational physics
url http://hdl.handle.net/20.500.11937/5582