Excitation of He+ to the 2 2S and 2 2P states by electron impact

A. C.H. Smith; M. E. Bannister; Y. S. Chung; N. Djuric; G. H. Dunn; A. Neau; D. Popovic; M. Stepanovic; B. Wallbank

doi:10.1088/0953-4075/34/17/104

Excitation of He⁺ to the 2 ²S and 2 ²P states by electron impact

A. C.H. Smith, M. E. Bannister, Y. S. Chung, N. Djuric, G. H. Dunn, A. Neau, D. Popovic, M. Stepanovic, B. Wallbank

Electrical & Chemical Operations

Research output: Contribution to journal › Letter › peer-review

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Abstract

The first absolute measurement of the cross section for excitation of a hydrogen-like ion is reported. The combined cross section for electron impact excitation of ground state He⁺ to the 2 ²S and 2 ²P excited states has been measured in the near-threshold region from 40.08 to 41.95 eV using the JILA/ORNL merged electron-ion beams energy-loss technique. The threshold step in the cross section is measured as (8.46 ± 1.52) × 10^-18 cm² at 90% confidence level of total uncertainty, which is approximately 20% larger than values calculated using close-coupling and variational methods. This contrasts with the long-standing disparity of nearly a factor of two between theory and normalized experiment for excitation to the 2 ²S state.

Original language	English
Pages (from-to)	L571-L577
Journal	Journal of Physics B: Atomic, Molecular and Optical Physics
Volume	34
Issue number	17
DOIs	https://doi.org/10.1088/0953-4075/34/17/104
State	Published - Sep 14 2001

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title = "Excitation of He+ to the 2 2S and 2 2P states by electron impact",

abstract = "The first absolute measurement of the cross section for excitation of a hydrogen-like ion is reported. The combined cross section for electron impact excitation of ground state He+ to the 2 2S and 2 2P excited states has been measured in the near-threshold region from 40.08 to 41.95 eV using the JILA/ORNL merged electron-ion beams energy-loss technique. The threshold step in the cross section is measured as (8.46 ± 1.52) × 10-18 cm2 at 90% confidence level of total uncertainty, which is approximately 20% larger than values calculated using close-coupling and variational methods. This contrasts with the long-standing disparity of nearly a factor of two between theory and normalized experiment for excitation to the 2 2S state.",

author = "Smith, {A. C.H.} and Bannister, {M. E.} and Chung, {Y. S.} and N. Djuric and Dunn, {G. H.} and A. Neau and D. Popovic and M. Stepanovic and B. Wallbank",

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doi = "10.1088/0953-4075/34/17/104",

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pages = "L571--L577",

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TY - JOUR

T1 - Excitation of He+ to the 2 2S and 2 2P states by electron impact

AU - Smith, A. C.H.

AU - Bannister, M. E.

AU - Chung, Y. S.

AU - Djuric, N.

AU - Dunn, G. H.

AU - Neau, A.

AU - Popovic, D.

AU - Stepanovic, M.

AU - Wallbank, B.

PY - 2001/9/14

Y1 - 2001/9/14

N2 - The first absolute measurement of the cross section for excitation of a hydrogen-like ion is reported. The combined cross section for electron impact excitation of ground state He+ to the 2 2S and 2 2P excited states has been measured in the near-threshold region from 40.08 to 41.95 eV using the JILA/ORNL merged electron-ion beams energy-loss technique. The threshold step in the cross section is measured as (8.46 ± 1.52) × 10-18 cm2 at 90% confidence level of total uncertainty, which is approximately 20% larger than values calculated using close-coupling and variational methods. This contrasts with the long-standing disparity of nearly a factor of two between theory and normalized experiment for excitation to the 2 2S state.

AB - The first absolute measurement of the cross section for excitation of a hydrogen-like ion is reported. The combined cross section for electron impact excitation of ground state He+ to the 2 2S and 2 2P excited states has been measured in the near-threshold region from 40.08 to 41.95 eV using the JILA/ORNL merged electron-ion beams energy-loss technique. The threshold step in the cross section is measured as (8.46 ± 1.52) × 10-18 cm2 at 90% confidence level of total uncertainty, which is approximately 20% larger than values calculated using close-coupling and variational methods. This contrasts with the long-standing disparity of nearly a factor of two between theory and normalized experiment for excitation to the 2 2S state.

UR - http://www.scopus.com/inward/record.url?scp=0035860225&partnerID=8YFLogxK

U2 - 10.1088/0953-4075/34/17/104

DO - 10.1088/0953-4075/34/17/104

M3 - Letter

AN - SCOPUS:0035860225

SN - 0953-4075

VL - 34

SP - L571-L577

JO - Journal of Physics B: Atomic, Molecular and Optical Physics

JF - Journal of Physics B: Atomic, Molecular and Optical Physics

IS - 17

ER -

Excitation of He⁺ to the 2 ²S and 2 ²P states by electron impact

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